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20 Years Wismut GmbHRemediation for the Future

20 Jahre Wismut GmbH

Energy

Text and editingFederal Ministry of Economics and TechnologyDr J. Becker & Dr G. Ruhrmann, Partnerschaft, ErftstadtWismut GmbH, Chemnitz

Design and productionPRpetuum GmbH, Munich

Picture creditsWismut GmbH, cover photograph: New Ronneburg Landscape

Printed by Silber Druck oHG, Niestetal

PublisherFederal Ministry of Economics and Technology (BMWi) Public Relations Division/L2D-10115 Berlin, Germanywww.bmwi.de

March 2011

The Federal Ministry of Economics and Technology was awarded the audit berufundfamilie® for its family-friendly staff policy. The certificate is conferred by the berufundfamilie gGmbH, an initiative of the non-profit Hertie Foundation.

20 Years Wismut GmbHRemediation for the Future

Energy

2

Table of contents

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1 Wismut uranium ore mining operations in Saxony and Thuringia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 Remediation goals and concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Engineering services, licensing process, monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4 Remediation sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

5 Stewardship sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

6 Public relations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

7 Arts collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56

8 Documentation on Wismut corporate history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

9 Summary and outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

Inhalt

Foreword

3

Celebrating 20 years of Wismut GmbH means giving the company credit for 20 years of successful remedial action in Saxony and Thuringia, including the mitiga­tion of environmental damage, the substantial reduc­tion of environmental impacts, the creation of live­able landscapes for the benefit of the people living in live­able former mining regions, and the creation of conditions and prospects for economic revival.

With German reunification in 1990, the Federal Republic of Germany has assumed the sole social and financial responsibility for the decommissioning and rehabilitation of immense legacies. By the end of 2010, the federal government had made available funds totalling some 5.4 billion euros to finance the remedial operations.

This brochure portrays the initial situation and the results achieved thus far in mine decommission­ing and remediating former mining areas to prepare them for future reuse. In addition, it provides an over­view of the tasks ahead. The presentation of this report is also a token of gratitude to the staff of Wismut GmbH and to everybody else involved in the Project for their outstanding achievements.

Federal Ministry of Economics and Technology

1Wismut uranium ore mining operations in Saxony and Thuringia

The legacies left behind by uranium ore mining were generated by more than 40 years of mining and pro­cessing of uranium ore in East Germany. As early as 1946, the then Sachsenerz Bergwerke AG started ura­nium mining from abandoned mine dumps, adits, and mine pits, under supervision of units of the Soviet military. To cover reparation claims, the mining com­panies operating in the Soviet occupation zone were transferred into Soviet ownership. Thus, the Soviet stock company Wismut was founded in 1947. The goal of the undertaking was to provide uranium for the nuclear armament programme of the Soviet Union. A large workforce, conscripted from across the Soviet zone of occupation, was forced to work in the ura­nium mines. Uranium mining and processing during that period was characterised by bad working condi­tions, complete disregard for nature and the envi­ronment, as well as reckless encroachments on popu­lation centres. Whole areas were confiscated and turned into prohibited zones: Wismut became a state within a state.

In 1954 the German Democratic Republic (GDR) got a share in what had been a purely Soviet stock company up to that time. The company was convert­ed into a Soviet­German stock company SDAG Wismut, with both partners holding 50 per cent of the shares. The basis for this change was an agreement conclud­ed between the governments of the USSR and the

GDR on August 22, 1953. This agreement was renewed in 1962 and was extended in 1975.

Annual uranium production peaked in 1967 with a rate of 7,100 tonnes. In 1990, production was still at some 3,000 tonnes of uranium. By the end of uranium ore mining on December 31, 1990, Wismut mining units had produced a total of some 231,000 tonnes of uranium, ranking the GDR according to latest find­ings as the world’s fourth largest uranium producer after the USSR, the United States, and Canada.

Following German reunification, the Federal Republic of Germany and the Soviet Union signed a transition agreement on October 9, 1990 under the provisions of which SDAG Wismut ceased its opera­tion on January 1, 1991. This put an end to uranium ore mining in Saxony and Thuringia.

In 1990, the environmental situation in the min­ing districts was characterised by enormous environ­mental degradation affecting a total surface area of some 3,700 hectares, including radioactively contami­nated mine dumps, tailings ponds, and plant areas located within a densely populated region. Past min­ing activities had marked the mine and mill sites of Ronne burg, Seelingstädt, Crossen, Schlema, Pöhla, König stein, and Dresden­Gittersee with their traces of devas tation. Uranium mining operations had released

4

Parking lot and pit shafts against a background of waste rock piles at Schlema (ca. 1965)

5

duction legacies were defined as and remain the company’s key mission and corporate purpose. The Federal Republic of Germany is its only shareholder, represented by the Federal Ministry of Economics and Technology.

Following the usual practice in countries with

planned economies, the SDAG Wismut had not set aside any financial reserves for future decommission­ing and rehabilitation work. As a consequence, the federal government had to allocate sufficient funds for the Wismut GmbH company to fulfil its mission.

The legal framework for the decommissioning and rehabilitation work is set forth in the Wismut Act as well as all other relevant regulations, laws and ordinances contained in German mining and radia­tion protection legislation in particular as well as in German soil protection and water legislation. Fur­thermore, under the provisions of the German unifi­cation treaty, two former GDR regulations containing specific provisions on the decommissioning of urani­um mines (Nuclear Safety and Radiological Protection Ordinance and Mine Dump Ordinance) continue to be applied. Moreover, the German Commission on Radiological Protection has issued a number of radio­logical protection principles concerning the release of contaminated areas, waste rock piles, buildings,

radio active materials into the atmosphere, into soils, and into the hydrosphere. More than 300 million cubic metres of waste rock material had been brought to the surface and dumped in 48 waste rock piles. Pro­cessing uranium ore into yellowcake had generated more than 160 million cubic metres of tailings sludges containing residual levels of uranium and other con­taminants. This situation made it imperative already in 1990 to initiate immediate action to eliminate haz­ardous risks, to close mines and pits, and to clean up and rehabilitate production sites.

The national Wismut GmbH – a federal responsibility

Under the terms of German unification, ownership of 50 per cent of the shareholdings of the binational company SDAG Wismut passed to the Federal Republic of Germany. Under the terms of the German­Soviet governmental agreement of May 16, 1991, the Soviet shareholdings were also transferred to the German side. As a consequence thereof, the Federal Republic of Germany assumed responsibility for the company as a whole. On December 20, 1991, with the coming into force of the Wismut Act of December 12, 1991, the company SDAG Wismut was changed into Wismut GmbH, a company under German corporate law. Site decommissioning and rehabilitation of uranium pro­

Schlema spa park with shade sail against the background of Hammerberghalde waste rock pile (2001)

6 1 Wismut uranium ore mining operations in Saxony and Thuringia

prehensive assessment of their ecological, economic as well as social aspects. This optimisation process also comprised considerations regarding the long­term stability and follow­up costs of the different approaches. Trade­offs between the various interests were conducted in close cooperation with the rele­vant state supervisory authorities and through dia­logue with municipal and district representatives of the affected areas.

The decision­making process had to acknowl­edge that a good many of the remediation operations were indeed intervention measures which have the capacity to mitigate environmental damage but can­not undo environmental impacts altogether. In the end, concepts were worked out through constructive cooperation with the regulatory bodies of the Free States of Saxony and Thuringia which built a safe and generally recognised basis for future remediation planning by Wismut GmbH. First site­specific remedi­al concepts were finalised by August 1991 and then continuously updated in accordance with growing expertise and know­how. They provide the basis for concrete design and planning of the various remedia­tion measures as well as for the annual work pro­grammes. All work projects are submitted by Wismut GmbH to the competent authorities of the Free States of Saxony and Thuringia for approval and licensing.

and materials originating from uranium ore mining. These principles are taken into consideration when assessing the need to remediate areas and facilities.

From mining to remediation company

A priority task to be addressed in the early 1990s was the restructuring of the company from a mining com­pany oriented toward the maximum production of uranium under the conditions of a planned economy into a modern private sector remediation company. On January 1, 1992, the numerous affiliated mine sup­port activities of the SDAG Wismut were split from the newly founded Wismut GmbH and privatised during the mid­1990s.

When uranium mining was terminated at the end of 1990, there were no ready concepts or plans available to initiate the pending remediation meas­ures. For this reason, remedial concepts for all task complexes had to be developed at short notice. A pre­requisite for the development of remedial concepts was the assessment of the existing environmental impacts and the establishment of an environmental database. The need for environmental restoration and the definition of concrete remediation goals were derived from the analysis of these data. This meant in particular that the various options and alter­natives had to be submitted to a thorough and com­

Decommissioned Mine

Decommissioned Prosess Plant

Wismut Head Office

Wismut Sites

7

sented in compliance with the 1976 Co­determination Act. Since 2009, the supervisory board has nine mem­bers in accordance with the One­Third Employee Representation Act.

Today, Wismut GmbH comprises the head office, based in Chemnitz, and seven rehabilitation units in Saxony and Thuringia. The corporate structure has been continuously adapted to the progress in remedi­ation in a bid to conduct remedial processes in a cost­effective manner.

Funding

With German unification the federal government has not only assumed sole social responsibility for the remediation of the legacies left behind by urani­um ore mining in Saxony and Thu ringia but has also taken on sole responsibility for financing the enor­mous tasks. Wismut GmbH is an institutional donee funded by the federal government. To complete the environmental restoration programme, the federal government has earmarked 7.1 billion euros, some 5.4 billion of which had been spent by the end of 2010 − 2.9 billion in Thu ringia and 2.5 billion in

The multitude and diversity of tasks to be ad ­dressed in developing remedial concepts required the pooling of international technical and scientific expertise and the involvement of a great number of German and foreign experts.

Organisation/corporate structure

One of the priorities among the tasks to be addressed following assumption of responsibility for the Wismut company by the federal government in 1990 was the restructuring of the company from a mining compa­ny oriented toward the production of uranium under conditions of a planned economy into a modern pri­vate sector remediation company. In the transition period leading to the founding of Wismut GmbH, the German side had already assumed managerial lead­ership as agreed during German­Soviet negotiations. For that period, the Federal Ministry of Economics and Technology had appointed an advisory board to act as an interim supervisory board. Upon the found­ing of Wismut GmbH, three executive officers and a supervisory board were appointed. Until 2009, the shareholders and employees each had six representa­tives sitting on the supervisory board, equally repre­

Financing and workforce development

461

359

311

248

203

146

0

100

200

300

400

500

600

700

mill. euro

0

5,000

1991 1992 1993 1995 2000 2005 2010

10,000

15,000

20,000

25,000

Number of Personnel30,000

SDAG Wismut Wismut GmbH Financing

Source: Wismut GmbH

27,800

6,700 5,600

4,600 3,100

2,200 1,500

577

8 1 Wismut uranium ore mining operations in Saxony and Thuringia

is a remarkable achievement made possible by good understanding among the parties involved, i. e. the Federal Ministry of Economics and Technology as owner, the supervisory board, management, staff, and the labour union.

The main goals set for workforce development –

to ensure the completion of remedial tasks in a good and workmanlike manner by experienced Wismut staff and to achieve socially acceptable workforce reduction – have been fulfilled.

Managerial tasks funded by the federal budget encompass decommissioning and rehabilitation pro­jects, employment promotion schemes, redundancy programmes and other personnel policy regulations for a socially acceptable staff reduction as well as extensive educational opportunities for more than 1,500 young people who have received training in a variety of trades with a promising future in the for­mer mining regions.

Wismut as an economic factor

For the past 20 years, Wismut GmbH has been mak­ing a major contribution to shaping improved living conditions and to the economic stabilisation of the former mining regions. Rehabilitation of areas is an

Saxony. Financing needs are established on the basis of the company’s annual work plans, which are adopted as part of the federal budget by the German parliament.

Workforce development

One of the major problems to be addressed during the early years following the termination of uranium ore mining was to adapt and size the workforce to meet the challenge of the forthcoming remedial action. At the time when uranium ore mining and processing ceased, Wismut’s workforce totalled almost 28,000 employees. Numerous jobs were lost during the initial years. Setting up two employment promotion schemes made it possible to streamline the production workforce in a socially acceptable manner. Close to 11,000 employees registered with those schemes and joined various employee develop­ment and job conversion training programmes.

Following the spin­off of mine support and auxil­iary units on January 1, 1992, Wismut GmbH had still some 6,700 employees on its payroll. In 2011 some 1,500 remain. That such drastic staff cuts could be car­ried out in a socially acceptable manner using various tools (employment promotion schemes, semi­retire­ment, and miners’ insurance compensatory payments)

Industrial zone established on former Paitzdorf plant area, Ronneburg Operations Office (2009)

9

ation of uranium mining legacies. In the course of the ongoing remedial process – including decommission­ing, remediation and preparation for reuse – Wismut staff have acquired vast scientific and technical know­how and developed state­of­the­art remedial technol­ogies of their own in dealing with radioactive mining legacies. Since the mid­1990s, demand for the compa­ny’s experience and the technical expertise has been growing from external, mainly international clients. Marketing of the know­how was initially assured by the corporate unity Wismut­Consult and since 2002 is performed by the wholly­owned subsidiary WISUTEC Umwelttechnik GmbH, which was privatised in 2010.

The Wismut environmental restoration project has emerged as a significant international reference project for the clean­up of radioactive legacies. Wismut GmbH has presented its comprehensive expertise and experience at a multitude of seminars, congresses, and workshops at the national and inter­national levels, and the company itself has also organ­ised a number of international forums for exchang­ing experiences on major issues of mine rehabilita­tion. Prominent partners in these efforts included the U.S. Department of Energy (DOE) as well as organisa­tions and firms from Canada and Australia. These exchanges were subsequently joined by Eastern Euro­pean and CIS countries which, like Wismut, were in the process of decommissioning their uranium indus­tries. This network of mine operators, remediation companies, regulators, and domain experts has estab­lished itself as the “Uranium Mining and Milling Remediation Multilateral Exchange Group” (UMREG) and organises topical symposia at regular intervals. Since 2009, these meetings are held in Vienna under the auspices of the International Atomic Energy Agency (IAEA).

important prerequisite to attract investors and ensure sustainable development. Achievements so far in clude the establishment of forest and grassland areas for recreational use, the reactivation of tourism, the set­tlement of new industrial plants as well as the instal­lation of a solar park. By implementing this environ­mental restoration project, Wismut and the subcon­tracted local firms make a major contribution to em ploy ment and job creation in the region. So far, Wismut GmbH has awarded third­party contracts totalling some 1.9 billion euros, including ca. 1 billion euros in Saxony and ca. 0.6 billion euros in Thuringia. These contracts usually cover the purchase of materi­als and equipment; the supply of energy, raw materi­als and fuels and the purchase of engineering and construction services.

Favourable urban development following com­

prehensive rehabilitation of mining legacies is out­standingly exemplified by the community of Bad Schlema in Saxony which has regained its former title as a spa town. Successful reclamation of former min­ing sites is also manifest in East Thuringia where areas rehabilitated by Wismut GmbH were to a large extent incorporated into the BUGA 2007 national hor­ticultural exhibition as the “New Ronneburg Landscape”.

International cooperation and exploitation of remedial know-how and expertise

From the outset of the remediation project, a priority was placed on making sure that the Wismut project drew on and benefited from the international exper­tise and experience that other countries – such as the United States and Canada – had gained in the remedi­

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2Remediation goals and concepts

Since 1990 Wismut GmbH is conducting the remedia­tion of the legacies of uranium ore mining left behind in Saxony and Thuringia. This clean­up work is aimed at removing the hazards generated by uranium ore mining and its legacies or at least diminishing such risks to an acceptable residual level and at restoring an environment that is ecologically largely intact and fit for reuse in compliance with the provisions of the Federal Mining Act. This is an indispensable prerequi­site for the economic revival of the regions affected by Wismut mining operations.

In an initial phase, concepts had to be worked out for the remediation of the mining legacies. The con­cept­building process had to identify solutions which were both ecologically effective and sustainable for the remediation of mines, waste rock piles, and tail­ings management areas as well as for the treatment of contaminated waters generated during and past remedial operations. What would happen to plant buildings, production facilities, and plant areas was also up for decision.

Mine remediation concept

The remediation concept for the mines at the Ronne­burg, Schlema­Alberoda, Pöhla, Königstein, and Dresden­Gittersee sites calls for the flooding of the

mines. Shutting off the pumps which dewatered the mines during operation will allow natural inflow of groundwater into the mines. Prior to initiating the flooding process, oils, greases, and chemicals will be removed from the mines with a view to minimising subsequent contaminant release via the aquatic path­way. In a next step, mine workings of low rock me ­chanical stability – and in particular near­surface cav­ities – will be backfilled with self­hardening material to prevent surface subsidence and ensuing mine damage. Backfill materials consist of a mixture of sand, water, and cement or power plant fly ashes. Shafts and adit openings are safely sealed and plugged with concrete. In the meantime, mine flood­ing at the Pöhla, Schlema­Alberoda, Dresden­Gitter­see and Ronneburg sites is almost complete. Flooding of the Königstein mine is not yet terminated.

Mine dump remediation concepts

Waste rock and overburden stockpiled in mine dumps of Wismut resulted from the development of the various ore deposits. Given their levels of natural­ly occurring radionuclides, their resulting specific activity is basically within a range that requires reme­diation for compliance with radiation protection leg­islation. Moreover, the waste rock material contains heavy metals which may be relatively easily mobilised

Beerwalde waste rock pile (2010)

11

such as e. g. iron, nickel, and copper, which have to be prevented to the extent possible from unrestricted access to groundwater and surface water. In addition, slopes of many waste rock piles were too steep, and there was a real risk of slope failure. Safe remediation of the waste rock piles is therefore required under mining, radiation protection and water legislation.

At Wismut waste rock pile remediation follows two different approaches: the concept of relocation whereby several waste rock piles are excavated and moved to a single location and the concept of remedi­ation in situ whereby the waste rock piles are remedi­ated in place. Which of the two concepts is followed in a given case is determined by site­specific condi­tions, cost­benefit considerations, and public accept­ance issues.

All but two smaller waste rock piles located to the south of the motorway at the Ronneburg site were relocated into the worked­out Lichtenberg open pit mine, while the Drosen and Korbußen waste rock piles located to the north of the motorway were banked against the Beerwalde waste rock pile. At the majority of waste pile sites in Saxony relocation was not feasible for lack of space or economic considera­tions. For this reason, these waste rock piles were almost without exception remediated in situ. Mine dumps which contain waste rock and overburden materials suitable for capping purposes at tailings management areas constitute an exceptional case as they are either in part or entirely relocated for place­ment atop tailings management areas.

The basic remedial concept applicable to all waste rock piles provides for enhancing long­term slope stability and covering the piles with mineral and vegetation supporting soils. The cover has a num­ber of functions to fulfil. It has to reduce infiltration of precipitation into the waste rock pile body in order to minimise the volume of contaminant­bearing seep­age waters. Furthermore, the cover shall prevent direct contact with the waste rock material and diminish the environmental impact of radioactive releases from rock to a level within the natural back­ground range. Finally, the waste rock pile cover must support vegetation growth.

In order to achieve the above mentioned goals, Wismut has designed a number of site­specific cover options. Their topmost element is a topsoil layer fol­lowed by mineral soils acting as moisture storage layer. Depending on conditions at the site, the cover may comprise an additional infiltration barrier made of clayey material. Grass seeding follows immediately after completion of the cover. This primary seeding serves as a protection against erosion and stabilises the newly established top soil layer.

Both landscape features newly constructed by the relocation of waste rock piles and piles remediated in situ have to be provided with farm roads and draining ditches for collection and discharge of surface run­off. The concept for the reuse of reclaimed waste rock pile surfaces recommends the establishment of a for­est and meadow landscape. The basic principle un ­der lying the landscaping of remediated waste rock piles provides for their contours and vegetation to blend in with the surrounding scenery.

Mine waste rock pile

Moisture storage layer(mineral soil, 2 lifts)

Top soil

Standard two layer mine dump covers exemplified on the case of the Schlema site

12 2 Remediation goals and concepts

Tailings management facility remediation concept

Residues generated during the processing of urani­um ores at Seelingstädt and Crossen – aka tailings – were deposited as slurries into the Culmitzsch, Trünzig, and Helmsdorf/Dänkritz tailings manage­ment facilities. Design of suitable stabilisation strate­gies was not an easy thing to do since there were no experiences available in Germany or abroad on how to address tailings pond remediation of that order of magnitude. Scientific investigations and studies as well as pilot­scale tests had to be performed before informed decision­making was feasible. In develop­ing promising remedial strategies, Wismut also sought the advice and expertise of foreign experts. In the end, in cooperation with the regulatory bodies and their consultants, “dry” in situ remediation with partial dewatering of the tailings was identified as the preferred option, since it presented the optimum trade­off between environmental benefit and costs. Based on this option, the remedial concept provides for the in situ remediation of all three tailings man­agement sites involving the removal of the superna­tant water and the capping of the tailings ponds with soil materials.

To a large extent the technology of cover build­ing had to be designed by Wismut themselves. In a first step following the removal of the supernatant water, a circa 1.5 metre thick interim cover was placed on top of the exposed tailings surface. As a rule, and this applies in particular to zones of fine­grained tailings, permeable waste rock, sand or grav­el are used to build the interim cover.

Covering the clayey­silty fine­grained tailings was a formidable challenge. In contrast to the solid sandy­grained tailings of the beach areas, here the low load­bearing capacity of the subsoil did not allow a straightforward placement of the cover material. In order to build a load­bearing surface for follow­up operations, the exposed fine­grained tailings were covered with geotextile and geogrid materials. The geotextile primary capping provides sufficient load­bearing capacity for the operation of low­weight equipment used to stitch up to 5 metres long wicks (aka vertical drains) into the tailings. It also serves as a support pad for the placement of the interim cover.

The superimposed load of the interim cover squeezes some of the pore water out of the fine­grained tail­ings; the expelled pore water rises along the vertical drains into the interim cover from where it runs by gravity flow to the lowest point of the pond surface for collection and pumping. The interim cover gradu­ally evolves into a load­bearing surface suitable for future remedial action.

Interim covering of Tailings

The next remedial step to follow is contouring. Dam slopes are flattened wherever required for stabil­ity or erosion protection reasons. The profile of pla­teau areas is regraded in a way to allow natural sur­face run­off. Given that deep fine­grained tailings sludges in particular will drain very slowly over ex ­tended periods of time under the ap plied superim­posed load, so­called deep­reaching vertical drains are driven through the interim cover down into the tailings in order to enhance settlement that comes along with drainage. Basically, settlements and defor­mations should have faded away for the most part before the final cover is put in place. To achieve this goal, drains are driven down up to locally ca. 25 to 30 metres below the tailings surface.

Eventually, the contoured surfaces are capped with 1.5 to 2 metres of final cover. Its primary pur­pose is to control the infiltration of precipitation into the tailings in order to minimise the generation of contaminant­bearing seepage. Final covers of tailings man age ment areas basically feature an identical se ­quence of layers, namely recultivation and storage layer and infiltration barrier which may vary in thick­ness or compaction depending on the properties of

13

the tailings material. Landscape planning for the reuse of covered tailings provides for afforestation of subareas as well as for the preservation of open grass­land areas.

Concept for the handling of industrial buildings and facilities

After termination of uranium production there was no further use for most industrial buildings and facili­ties. Only few units are still being used for ongoing remedial work. These units will also be dismantled and demolished once remediation will be completed. The concept for dismantling and demolition stipu­lates that radioactively or chemically contaminated scrap and demolition rubble shall be disposed of within tailings management areas and waste rock piles. Uncontaminated scrap and scrap decontami­nated by sand blasting shall be recycled. In contrast, uncontaminated demolition rubble shall be used for road construction purposes on reclaimed Wismut areas.

Concept for the reuse of rehabilitated areas

Areas contaminated or otherwise affected by mining activities and being attributed to Wismut have to be prepared for profitable reuse in compliance with the

Schematic diagram of interim cover placement on tailings pond

Federal Mining Act. This does not compellingly imply, however, that the proper shaping of the ground sur­face would tantamount to the restoration of pre­min­ing conditions. In practice, the development of con­cepts for the reuse of individual areas at Wismut is guided by existing regional land development and zoning plans. The actual need for remediation of an area is determined by the degree of the established contamination and the type of envisaged reuse. The release of areas for housing development, for indus­trial, commercial, agricultural or forestry reuse is pri­marily subject to compliance with the criteria recom­mended in the radiological protection.

Green space at Kanigsberg, Ronneburg Operations Office (2009)

14 2 Remediation goals and concepts

In accordance with regional land development and zoning plans, forests or green spaces are the pre­ferred types of reuse for the vast majority of areas rehabilitated by Wismut. Only a few remediated plant areas are eligible for commercial or industrial reuse.

The concept for the remediation of waste rock pile footprints, plant areas and roadways and railbeds basically stipulates that all ground contamination be removed. On cleaned­up areas, foundations of demol­ished buildings and facilities are removed down to a minimum depth of 1.5 metres below ground level.

Concept for the handling of contaminated waters

Both during controlled mine flooding and after its completion, flood waters will daylight which are con­taminated with uranium, radium, heavy metals, and arsenic. The same is true for supernatant and pore waters which have to be removed by pumping for

9

8

7

6

5

4 3

2

1

FeedHCl

CO2

air

BaCl

FeCl3

Milk of Lime Flocculant

HCl

Discharge toCulmitzsch

To storage facility

Cement 1 Air blower2 CO2 strip column3 Neutralisation tanks4 Lamella thickener5 Filter6 Storage tank7 Plate and frame filter8 Mixing machine9 Transport container

2

Flowsheet of the Seelingstädt water treatment plant using the lime precipitation process.

tailings dewatering purposes as well as for seepage from covered tailings management areas. Since these waters are radioactively and chemically contaminat­ed they have to be treated in water treatment plants prior to discharge into receiving streams.

Wismut operates eight water treatment plants. Six of them use a flowsheet of precipitation with lime. By addition of milk of lime, barium chloride, and iron chloride heavy metals, uranium, radium, and arsenic are removed from the feed water as a low solubility precipitate. Water treatment residues are disposed of in engineered cells in waste rock piles and tailings management areas. The two exceptions are the unit for the treatment of seepage from waste rock pile #371 at the Schlema site and the unit for the treat­ment of the flood water from the Pöhla mine. At the Pöhla site, contaminants are precipitated by addition of barium and iron chloride without lime slurry; and the seepage from waste rock pile #371 is treated in an ion exchange unit.

15

Comprehensive planning work is required to trans­late remediation concepts into actual remedial action. Such planning is in many cases based on detailed engi neering services which, for the most part, also serve to underpin licence applications. The broad variety of remedial goals is reflected in the range of engineering branches and supporting applied natu­ral sciences involved: mining, geotechnics, soil me ­chanics, mine surveying, civil engineering including statical calculation, chemical engineering, process engineering, plant construction, electrical engineer­ing, measurement and control systems engineering, transportation, hydraulics, road construction, energy supply, logistics, forestry as well as radiological pro­tection. Science applications comprise geology, hy ­drogeology, radioecology, and me te orology. Mathe­matical modelling is used to assess the impact of vari­ous remedial options on water, air and soil quality as well as radiation exposure of critical groups of the public.

Initially, these engineering services were aimed at

3The development of various remedial options,

3Performing technical feasibility studies, and

3Investigating the efficiency and sustainability of the proposed remedial options.

The findings served as a basis in the process of choos­ing a preferred option which in addition to technical feasibility would also comply with requirements regarding

Numerical settlement computation for Culmitzsch tailings pond

3Safe working conditions and protection of the public during the execution of the required remedial operations,

3Total rehabilitation expenditure including fol­low­up long­term care and maintenance tasks, and

3Public acceptance.

Moreover, engineering services served as a basis for optimising work processes and enhancing quality control.

Engineering services not available at Wismut are being contracted out to recognised specialised firms to profit from their expertise.

Already at the time when mining operations ceased 20 years ago, Wismut sought contact with in ­ternationally operating engineering firms in the field of mine remediation with a view to enhancing the company’s mine engineering expertise and making it available for integration into its conceptual planning. In the meantime, Wismut’s mine remediation know­how is in demand nationally and internationally. A case in point is Wismut’s cooperation with the Czech company DIAMO in remediating the abandoned in situ leach mines of Stráž pod Ralskem and Königstein and optimising treatment options for effluents from flooded uranium mines. In Hungary, the Mecsek­Öko company successfully terminated the rehabilitation of uranium mining legacies using Wismut know­how and expertise. Remediation of the Sillamäe tailings

3Engineering services, licensing process, monitoring

+0.1

0.0

-0.1

-0.2

-0.3

-0.4

-0.5

-0.6

-0.7 m

Surface Contouring

Bed Rock

Sandy Tailings

FineTailings

SN

16 3 Engineering services, licensing process, monitoring

pond of the SILMET processing plant in Estonia was successfully completed in 2008 after some 10 years of project duration, with Wismut GmbH acting as plan­ning advisor and consultant.

Briefing of regulatory agencies early on in the engineering planning stage has turned out to be con­ducive to speeding up the licensing process, as it allows an informed discussion of technical and legal issues with the experts of the licensing authorities in Saxony and Thuringia.

Starting in 1990, Wismut has submitted more than 8,000 licence applications. Some 4,300 licences were granted in Saxony, approximately 3,700 in Thu­ringia and ca. 60 licenses were awarded for cross­bor­der clean­up. Almost half of the licences were granted under the provisions of the mining legislation, and about 1,000 permits each were awarded under radia­tion protection legislation and water legislation, respectively. Permits granted under environmental protection legislation were in excess of 1,300.

Coordination of remediation planning with com­munities in the area is of particular importance. To the extent possible, reclamation at Wismut sites has to take local and regional land use planning into con­

sideration. To this end, local government representa­tives and Wismut GmbH meet at regular intervals.

On behalf of the Federal Ministry of Economics and Technology (BMWi) a third party consultant which is mandated to assess the implementation of decommissioning and remediation measures for solid practice and cost efficiency is also monitoring the licensing process. For more specific issues, the

Monitoring along Postersteiner Sprotte

Mobile measuring station for radon, dust, and precipitated dust

17

Federal Institute for Geosciences and Natural Re ­sources and their expertise come into line. The Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) exercises federal supervi­sion over licensing under radiological protection leg­islation of the Free States of Saxony and Thuringia. In this respect, the BMU utilises the expertise of the Federal Office for Radiation Pro tection (BfS) and con­sultants.

Impacts and results of remediation activities are registered by a comprehensive monitoring system. Moni toring comprises radioactive and non­radioac­tive substances in water, soil and air. In addition, meteorological data are collected and soil physical

Evolution of releases via the atmospheric and aquatic pathways

1992 1994 1996 1998 19991991 1993 1995 1997 2000 2002 2004 2006 20082001 2003 2005 2007 2009

1992 1994 1996 1998 19991991 1993 1995 1997 2000 2002 2004 2006 20082001 2003 2005 2007 2009

Rado

nRa

dium

, Ura

nium

Use

d ai

rW

ater

Air Pathway

Water Pathway

Radon, 1012 Bq

Source: Wismut GmbH

Used air, 109 m3

Uranium, t Ra-226, 109 BqWater, 106 m3

0

200

400

600

800

1,000

1,200

1,400

1,600

0

10

20

30

40

50

60

70

80

90

100

0

2

4

6

8

10

12

14

16

18

20

0

5

10

15

20

25

30

35

parameters established from cover systems of waste rock piles and tailings management areas to confront their evolution with engineering and model calcula­tion forecasts. Based on monitoring results, changes in environmental impacts occurring in the course of remediation are recorded, recorded data are stored in data banks, and the findings are documented in re ­ports submitted to the regulators and the public. In this way, compliance with legal and regulatory stand­ards and legislation is documented and the remedial success made obvious.

By the end of 2010, Wismut operated a total of

some 2,000 measuring stations. These stations moni­tor the atmosphere (radon, dust, long­lived radionu­

18 3 Engineering services, licensing process, monitoring

clides, both dust­borne and in precipitated dust) as well as receiving streams and groundwater (radionu­clides, heavy metals, further contaminants). Other measuring networks are operated to register poten­tial movements at ground surface which could be caused by the collapse of underground cavities, tail­ings dewatering or mine flooding. Soil and biomass sampling is conducted to track contamination by radionuclides or other contaminants.

The number of required measuring stations will decrease with further progress of remedial work and the transition of reclaimed objects into the post­reme­dial phase. At the end, only measuring stations will remain active which are required for key measuring networks. These networks are designed to meet the

needs of long­term post­remediation monitoring. Besides groundwater measuring points they also comprise measuring stations for surface water and seepage to ensure long­term hydrological and hydro­chemical monitoring of individual objects or groups of objects. Any measuring station not eligible for inte­gration into the key measuring networks for the aquatic pathway shall be gradually placed out of ser­vice. Depending on remedial progress at the various sites, this process will continue for several years and will certainly not be completed prior to the full reme­diation of the Culmitzsch tailings management site.

Measurement results registered to date demon­strate a significant improvement of environmental quality.

Groundwater monitoring, Königstein

19

Ronneburg

Initial situation

When uranium ore mining was terminated on De cem­ber 31, 1990, the Ronneburg site comprised the min­ing units of Schmirchau, Paitzdorf, Beerwalde, and Dro sen. The Schmirchau mining unit also comprised the Reust mine and the worked­out Lichtenberg open pit, and the Beerwalde unit also comprised the Kor­bußen mine. In 1991/92, these units were gradually merged to form the Ronneburg Rehabilitation Unit as from January 1, 1993.

When mining was terminated the legacies left

behind at Ronneburg comprised the pit sites with a total of 38 major shafts, 3 adits, mine drifts of a total length of 1,043 kilometres and open mine workings of 26.7 million cubic metres, as well as the residual Lich­tenberg open pit with a residual volume of 84 million cubic metres. Approx imately 188 million cubic metres of waste rock and overburden were scattered among 16 mine dumps. Plant areas including waste rock pile footprints and the surface of the residual Lichtenberg open pit extended over an area of 1,670 hectares. The groundwater depression cone due to mining opera­tions extended for more than 50 square kilometres.

Remediation concepts

Following approval by the regulatory bodies, remedia­tion of mining legacies in the Ronneburg mining dis­trict was implemented on the basis of the subsequent concepts:

3 Mines: Removal of substances with the potential to pollute the incoming groundwater (grease, oil etc.) and flooding up to natural groundwater levels.

3 Buildings and Structures: Complete dismantling and demolition.

3 Lichtenberg Open Pit Mine: Backfilling with waste rock material.

3 Waste Rock Piles: Relocation and concentration at one single location each north and south of the motorway.

3 Operation Areas: Preparation for reuse of former mining areas predominantly for agricultural and forestry purposes as well as for industrial and commercial reuse.

3 Contaminated Waters: Capture of all daylight­ing contaminated waters and treatment to reach compliance with authorised discharge limits.

4Remediation sites

Conical piles and Ronneburg plant area before remediation (1991)

20 4 Remediation sites

Remediation achievements

Flooding of underground minesFlooding of the mining fields located to the north and south of the motorway of the Ronneburg mining dis­trict represented a major challenge. Elaborate pre­paratory work, both scientific and technical, was required to assess the impacts of mine flooding on aquifers and surface water bodies located down­stream of the mines.

The preparatory studies revealed that prior to flooding the mines all pit shafts and near­surface mine workings had to be backfilled with cohesive stowing material down to a depth of 100 metres in order to preclude future surface subsidence. Identical precautions had to be taken with regard to mining cavities near protective pillars as well as beneath the town of Ronneburg. Mine workings at the Beerwalde and Drosen subsites had also to be backfilled in order to protect aquifers located north of a geological fault zone („Crimmitschau fault“). Underground remedial work initiated in 1991 was completed in 2000. Ap ­prox imately 5.8 million cubic metres of mining cavi­ties were backfilled.

Once mine workings and pit shafts had been re ­mediated and backfilled by 1998, overall flooding of mining fields located south of the motorway was initi­ated. Flooding of mining fields located north of the motorway commenced in 2000. In essence, all mine

workings are completely flooded. Replenishment of dewatered pore spaces, fissures and cracks of the cone of depression with groundwater and the subse­quent groundwater rise to its natural level is still going on.

Modelling of anticipated flood behaviour for the mining districts located north and south of the motorway had revealed very early on that groundwa­ter replenishment would very probably result in groundwater emergence in the Gessental valley and that this groundwater would be contaminated by rock contact in the flooded mine workings. Preparing for such a scenario, in 2001 Wismut established a groundwater collection system on the bottom of the Gessental valley and along the north­western edge of the Lichtenberg open pit mine. Zones along the Posterstein Sprotte and Beerwalde Sprotte creeks were identified as further potential decant areas.

The water collection system is a combination of horizontal and vertical drainage installations. Ground ­water intercepted by this collection system drains to a pump station located in the Gessental valley from where is pumped via a 3.8 kilometre long pressure pipe to the Ronneburg water treatment plant.

In August 2006, the groundwater had risen to the lowermost section of the groundwater collection sys­tem.

Residual Lichtenberg open pit (1992)

21

Dismantling and demolition of structures and facilitiesThe termination of uranium ore mining made the mine hoisting complexes consisting of 19 pit shafts as well as 19 mine ventilation shafts redundant. For the associated ore bins and conveyors, ore loading and transportation facilities, substations, transformer sta­tions, power grid for electric supply, boiler houses, distribution stations, steam pipe networks for heat supply, pumping stations, water storage tanks, waste water treatment plants, piping systems for drinking water and process water supply as well as sewage management, repair shops and storage houses as well as administrative buildings, kitchen buildings and staff restaurants and sanitary facilities there was no further use at the Ronneburg site. Starting in 1991, facilities and buildings were dismantled and demol­ished. To date, only the administrative buildings, repair shops, and storage houses of the former Lich­ten berg mine are still in use. In the meantime, all other facilities and buildings of the former spaciously laid out mining district are gone.

By the end of 2010, dismantling and demolition of facilities and buildings had generated some 70,000 tonnes of scrap and 285,000 cubic metres of demoli­tion rubble. Radioactively contaminated scrap as well as both radioactively and chemically contaminated demolition rubble were disposed of in the residual

Lichten berg open pit. Uncontaminated or decontami­nated scrap was sold.

Waste rock pile remediation and backfilling of open pit mineWaste rock pile remediation at the Ronneburg site was completed in 2008. Except for the Beerwalde mine dump and waste rock pile #381 in the Gessental valley, Diabashalde dump and all low­grade ore, waste rock and overburden piles were completely dug up and removed. The ma terial contained in the waste rock piles located south of the motorway was used to backfill the worked­out Lichtenberg open pit mine. The Drosen and Korbußen waste rock piles located north of the motorway were dug up and banked against the Beerwalde waste rock pile (Table 1).

Relocation of waste rock material into the worked­

out Lichtenberg open pit mine resolved several prob­lems at one go. On the one hand, the worked­out open pit mine was backfilled, which otherwise would have filled up with radioactively and chemically con­taminated groundwater in the wake of mine flood­ing. On the other, there was waste rock at some loca­tions which contained up to 5 per cent of pyrite which forms acid when reacting with atmospheric oxygen and water. To avoid the need to intercept and treat acid drainage for decades to come, pyrite­laden waste rock had to be concentrated at a single location and

Mound atop backfilled Lichtenberg open pit (2010)

22 4 Remediation sites

disposed of in a way that would preclude pyrite to come into contact with atmospheric oxygen. Placing waste rock with elevated acid generation potential at the bottom of the open pit mine did meet this requirement in an ideal manner since the backfilled material would for the most part be submerged below the groundwater table once flooding was com­pleted. Groundwater provides efficient shielding against access of air.

The available pit volume of 84 million cubic metres was too small to accommodate the total vol­ume of 132 million cubic metres made up of relocated waste rock (Table 1), excavated contaminated soil and rubble from the demolition of buildings and structures. The surplus material was used to build up a mound atop the backfilled open pit. In commemo­ration of the Schmirchau community which had to make way for the development of the open pit mine, the mound is called “Schmirchau Height”. This land­scape feature and the reclaimed Nord halde footprint in the Gessental valley were integrated as „New Ronneburg Landscape“ into the grounds of the 2007 National Horticultural Exhibition.

The Lichtenberg fill body is being provided with

a final cover of 1.6 metre thickness of which 91 per cent

were completed by the end of 2010. Engineered cells within the fill body will accommodate excavated con­taminated soil as well as immobilised water treat­ment residues from the Ronneburg water treatment plant. Forests and green spaces are the intended reuse options for this 222­hectare area. By the end of 2010, afforestation had been completed on 51 hec­tares. A network of logging roads and hiking trails totalling 19 kilometres will be established for forest management and tourism development around the “Schmirchau Height”. By the end of 2010, 17 kilome­tres of that network were completed.

The rationale behind excavating and banking the Drosen and Korbußen waste rock piles against the Beerwalde pile was similar to that for relocating the waste rock piles into the worked­out Lichtenberg open pit, namely to concentrate the waste rock mate­rial of the three piles located north of the motorway in a single location. This approach was more cost­effective than to remediate the three piles individual­ly in situ.

The final cover of the Beerwalde waste rock pile consists of 0.40 metre infiltration barrier and 1.5 metre moisture storage layer on top. Vegetation of the newly created landscape feature finalised the

Relocation scheme for waste rock piles south of A4 motorway at Ronneburg

Waste Rock Relocation into Open Pit Lichtenberg 3 Gessen heap leach pile Relocation: 1990–1995 Volume: 7.6 mill. m³ 3 North waste rock pile Relocation: 1998–2003 Volume: 31.3 mill. m3

3 Stacked waste rock pile Relocation: 1993–2006 Volume: 70.1 mill. m3

3 Reust terraconic waste rock piles Relocation: 2004–2007 Volume: 6.4 mill. m3

3 Paitzdorf terraconic waste rock piles Relocation: 2005–2006 Volume: 8.0 mill. m3

1

2

3

4

5

23

remediation of the Beerwalde waste rock pile in 2003. Since then, young forest plantations have been grow­ing vigorously.

Excavating and moving waste rock piles at the Ronneburg site involved off­highway equipment.

A fleet worth some 45 million euros of up to 75 mas­sive earthmoving machines including dump trucks, excavators, shovels, and dozers excavated and moved up to 40,000 cubic metres of waste rock material a day in its heyday.

Shift change during waste rock pile relocation into Lichtenberg open pit mine (1998)

Type of Remediation Volume, 106 m3 Relocation Period

Remediation in situ

Beerwalde pile 4.5

Waste Rock pile #381 0.8

Diabashalde dump 0.2

Total 5 .5

Relocation into Lichtenberg open pit

Absetzerhalde pile 70.1 1993 – 2006

Nordhalde pile 31.3 1998 – 2003

Conical piles Paitzdorf 8.0 2005 – 2006

Gessenhalde pile 7.6 1990 – 1995

Conical piles Reust 6.4 2004 – 2007

Waste rock pile #370 1.4 2003

Waste rock pile #4 1.1 2006 – 2007

Waste rock pile #377 0.4 2004

Schutzdamm Ronneburg 0.1 2007 – 2008

Total 126 .4

Relocation to Beerwalde waste rock pile

Drosen waste rock pile 4.0 1997 – 1999

Korbußen waste rock pile 0.5 2000 – 2001

Grand Total 4 .5

Table 1: Waste rock pile remediation at Ronneburg site

24 4 Remediation sites

Operation areas and waste rock pile footprintsIn 1992, an area of approximately 1,520 hectares at the Ronneburg site was owned by Wismut GmbH. This property was for the most part composed of operation areas of the former mining units as well as of waste rock footprints and roadways and railtracks. Of that total, some 1,100 hectares were in need of remediation. The sites either had an elevated natural radioactivity or were contaminated with heavy met­als and hydrocarbons or showed multiple contamina­tion by two or three of the above types of contami­nants. Depending on concentration levels of the hydrocarbons, the contaminated soil excavated dur­ing ground remediation was either integrated into the fill body of the Lichtenberg open pit or disposed of at the Lichtenberg disposal cell for materials with multiple contamination operated by Wismut. Given that large quantities of soil with multiple contamina­tion were excavated from 1997 through 2001, Wismut established a biological treatment unit at Ronneburg where hydrocarbon decomposition was performed by bacterial oxidation.

To date, some 830 hectares of former plant areas, roadways and rail tracks as well as waste rock pile footprints have been reclaimed. Operation areas and waste rock pile footprints at the former Drosen and Korbußen mining units as well as the footprints of waste rock piles #370, #377 and of the Gessenhalde

pile have been fully reclaimed. Remediation of the Nordhalde, Absetzerhalde, Paitzdorf and Reust waste pile footprints will for the most part be finalised by 2015.

In line with regional land development planning for Eastern Thuringia the reclaimed areas will be turned into forests and green spaces for the most part. Operation areas of the former Beerwalde, Schmirchau, and Paitzdorf mining units were reclaimed for com­mercial and industrial reuse. Installation of a photo­voltaic plant at the site of the former Schmirchau mining unit in 2009 is a case in point. Planning is under way for a second photovoltaic plant at the foot­print of the former Reust waste rock pile. Under the motto „Resurrektion Aurora“ an open­air museum depicting the history of uranium mining by Wismut as well as a sculpture park were inaugurated at the site of the former Drosen mining unit on the occasion of the national horticultural exhibition in 2007.

Collection and treatment of contaminated watersIn August 2006, the groundwater had risen to the level of the water collection system established in the Gessental valley. Parallel to the groundwater rise the volume of intercepted groundwater has risen from less than 20 cubic metres per hour at the beginning to a volume in excess of 400 cubic metres per hour. Previously unknown hydraulic shortcuts caused the

Conical waste rock piles at Reust mine site before remediation (1991)

25

emergence of contaminated groundwater in the Gessental valley at sites located outside the sphere of influence of the collection system where the system hence failed to intercept them. Locally emerging water is currently intercepted in near­surface drain­ages and catchment ditches and then pumped to the Ronneburg water treatment plant as well. In 2008 and 2009, contaminated groundwater emerged along the Postersteiner Sprotte and Beerwalder Sprotte creeks as predicted. In co­ordination with the regulatory authorities, temporary collection systems were established here as well. The water is piped to appropriate locations from where it is returned to the mine.

To terminate the temporary water catchment measures in the Gessental valley, the existing ground­water collection system will have to be enhanced. This in turn will require the lowering of the flood water level by about 25 metre. However, before pro­ceeding with this plan, the capacity of the Ronneburg water treatment plant has to be expanded to treat 750 cubic metres per hour. The upgraded plant is expected to come on stream in autumn of 2011.

The Ronneburg water treatment plant is using lime precipitation to treat the contaminated waters. Immobilised water treatment residues are disposed within the Lichtenberg fill body. Treated waters are

discharged into the Wipse streamlet from where they reach the Weiße Elster River.

Since its commissioning, the plant has treated some 17.5 million cubic metres contaminated surface run­off and groundwater. Capital costs for the con­struction of the water treatment plant including the feeder pipe amounted to 17 million euros. Upgrading of the plant will require an additional 5 million euros.

Outlook

Remedial operations at the Ronneburg site will for the most part be finalised by 2015. Work to be final­ised by that date involves mainly area remediation projects. Demolition of repair shops, storage houses, administrative buildings, associated roadways and rail tracks as well as a number of water storage ponds which are currently still required for the execution of remediation measures is slated to follow after 2015. Subsequent to this work, the cleared areas will be renaturated.

Long­term tasks to be accomplished after remedi­ation is complete will include water treatment, moni­toring as well as care and maintenance duties. The period of time during which water treatment will be required cannot be specified at the present time.

Footprint of the Reust waste rock piles after remediation (2010)

26 4 Remediation sites

Seelingstädt

Initial situation

At the time when ore processing was terminated at the end of 1990, the Seelingstädt site comprised the Seelingstädt mill as well as the two tailings manage­ment areas of Culmitzsch and Trünzig. Commis­sioned in 1960, the Seelingstädt mill was Wismut’s largest and most advanced processing site. The mill processed a total of 110 million tonnes of ore coming for the most part from Ronneburg, but for some time also from the Aue district as well as from Königstein and Dresden­Gittersee. The site of the mill was chosen for its proximity to the two worked­out open pit mines of Culmitzsch and Trünzig which could be used to accommodate the processing residues.

The Seelingstädt processing facility occupied an area of 83 hectares. Of that total some 25 per cent were built­up. In addition to ore processing facilities, the premises also contained a sulphuric acid plant and an industrial power plant. On balance, there were more than 300 buildings. Depending on the type of ore, the Seelingstädt mill either used an acid (sulphuric acid) or alkaline (sodium carbonate) flow sheet.

The ore processing residues, also known as tail­ings, were discharged into the Trünzig tailings man­agement facility from 1960 through 1967 and from 1967 till the end of ore processing in 1990 into the Culmitzsch tailings management facility. Due to the process technology, each facility was divided by a dyke into two ponds for a separate storage of residues from the acid and alkaline leaching process.

The Trünzig and Culmitzsch tailings manage­ment facilities covered a total surface of about 350 hectares and contained some 104 million cubic metres of tailings (Table 2). In 1992, the volume of supernatant water in the ponds amounted to some 2.4 million cubic metres.

Both tailings ponds are bounded by dams and overburden dumps. The dumps were piled up during the development of the Culmitzsch and Trünzig as well as of the Sorge­Settendorf and Gauern open pit mines. Out of a total of 9 overburden dumps, only the Waldhalde, Jashalde, Lokhalde and Südwesthalde dumps with an overall volume of 55 million cubic metres are still owned by Wismut (Table 3).

Some slope sections of the Waldhalde and Süd­westhalde dumps have to be flattened to achieve last­

Seelingstädt processing plant (1991)

27

ing slope stability. Material at other parts of the Wald­halde dump must either be covered or removed for compliance with radiation protection regulations.

Remediation goals/concepts

Following approval by the licensing authorities, remediation of legacies at the Seelingstädt site was conducted on the basis of the subsequent concepts:

3Plant Facilities and Buildings: Except for the laboratory building, dismantling and demolition of all other structures.

3 Tailings Management Facilities: Removal of supernatant water, followed by interim cover placement, contouring, placement of final cover on tailings; vegetation and afforestation of cov­ered tailings.

3Overburden Dumps: Flattening of low­stability slopes, relocation of low­grade ore from Wald­halde, and some excavation of material to be used for recontouring and final cover placement of both tailings management areas. Afforestation of newly recontoured dumps to be left in place.

Trünzig tailings management facility (1991)

Culmitzsch Trünzig

Tailings area ha 234 115 Pond A ha 158 67 Pond B ha 76 48Tailings volume 106 m3 85 19 Pond A 106 m3 61 13 Pond B 106 m3 24 6Solids 106 t 91 19 Pond A 106 t 64 13 Pond B 106 t 27 6Maximum Tailings thickness Pond A m 72 30 Pond B m 68 24Volume Supernatant water 106 m3 2.4 0.08 Pond A 106 m3 2.1 – Pond B 106 m3 0.3 0.08Maximum Water depth Pond A m 7.9 – Pond B m 2.4 2.3

Table 2: Parameters of Culmitzsch and Trünzig tailings management areas (1990)

28 4 Remediation sites

3Operation Areas: Rehabilitation of former plant premises and of Lokhalde footprint for reuse as forests and green spaces.

3Contaminated Waters: Treatment of contami­nated supernatant waters as well as contaminat­ed seepage and run­off intercepted near tailings management areas in Seelingstädt water treat­ment plant. Treatment of seepage will have to con­tinue until compliance with discharge standards.

Remediation achievements

Plant facilities and buildingsDismantling and demolition of plant facilities were for the most part carried out from 1997 to 2003. Demolition work generated some 60,000 tonnes of scrap and 230,000 tonnes of demolition rubble.

Contaminated demolition rubble was crushed and used to build interim covers on tailings manage­ment areas. Uncontaminated rubble was also used to build roadways across tailings management areas.

Scrap from buildings and facilities where verifia­bly no radioactive materials were handled, e.g. the sulphuric acid plant and the industrial power plant, were directly recycled, certified by a declaration of plausibility. Steel scrap from radiation protection areas, on the other hand, had to be measured for total alpha surface activity using a procedure specifically designed for Wismut applications. In case of surface activity levels below the release standard of 0.5 Bec­querel per square centimetre the scrap was released for smelting. Large quantities of contaminated steel scrap could be recycled after decontamination by sand blasting. Decontamination waste and unusable contaminated scrap were disposed of in engineered cells at the Culmitzsch tailings management facility and plugged with concrete.

An unpolluted sector of the former plant premis­es was sold and is now used for commercial purposes. The laboratory and pilot­test building is the only sur­viving structure on the remaining premises. Also still in operation is the unloading station of the Wismut branch line which is used for the supply of sand and

Footprint areaha

Max . Height above footprint in m

Volumen106 m3

Lokhalde dump 81 23 16

Waldhalde dump 73 36 21

Jashalde dump 22 23 4

Südwesthalde dump 42 41 14

Total 55

Table 3: Parameters of overburden dumps at Seelingstädt (1990)

Trünzig tailings management facility (2010)

29

gravel destined for the interim cover of the Culmitzsch tailings management area as well as top­soil destined for the recultivation of the reclaimed plant premises.

Tailings management facilities Initial remediation work at the Culmitzsch and Trün­zig tailings management facilities began as early as 1990 and 1991, respectively, when interim covers were placed on exposed tailings beaches in order to elimi­nate immediate risks and reduce contaminant disper­sal by windblown dust. In the period that followed, supernatant water was removed and the areas ex ­posed due to the falling water level were then gradu­ally capped with an interim cover.

Placement of interim covers on ponds A and B of the Trünzig tailings management facility was final­ised in 1995 and 2001, respectively. The interim cover on pond B was completed in 2006. Full interim cover on pond A is slated for 2014; some 95 per cent are presently in place. Building the interim cover of the Trünzig tailings management facility consumed some 1.1 million cubic metres of earthen material, for the main part excavated during the renaturalisation of the Finkenbach valley which during production times was used as a dumping ground for overburden

material. Some 3.5 million cubic metres of sand, grav­el, and material excavated from the Lokhalde dump were needed to complete the interim cover on the larger Culmitzsch tailings management facility.

Started in 2001, recontouring of dam and plateau sections at the Trünzig tailings management facility is nearing completion. Final cover placement across the entire facility is to be completed by 2012; current­ly some 85 per cent have been put in place. The gently undulated plateau area was designed in a way to allow surface run­off from pond A to discharge to wards the Culmitzsch lowland and from pond B to wards the Finkenbach valley. Contouring and final cover build­ing at Trünzig tailings management facility used up some 6.5 million cubic metres of overburden material.

Contouring work on the Culmitzsch tailings man­

agement facility began in 2007 by flattening the Nord ­damm for stability reasons. Forestry roads were built on the berms of the recontoured Norddamm and the adjacent Jashalde dump as well as along the toe of the Nord damm. To collect surface run­off riprap channels and ditches were constructed. Work on the Nord­damm is completed. Contouring work is under way on pond B. Süddamm and pond A are slated to follow in a couple of years. According to current planning,

Culmitzsch tailings management facility (2010)

30 4 Remediation sites

contouring and final covering of the entire tailings management facility is to be finalised by 2022. In addition to the 3 million cubic metres already used up, some 18 million cubic metres more of overburden material will have to be moved to the Culmitzsch tail­ings management facility for contouring and cover building purposes.

In the end, the plateau section of the Culmitzsch tailings management facility is to emerge as a slightly undulating landscape which discharges its run­off towards north. The reclaimed areas are to be afforest­ed for the main part with coniferous and deciduous trees to form mixed woodland. Partial areas along the external dams and the pond centres are designed as green spaces.

Overburden dumpsMaterial needed for contouring and final cover build­

Reuse concept for Culmitzsch tailings management facility

ing at the Trünzig and Culmitzsch tailings manage­ment facilities is being provided by the complete excavation of the Lokhalde dump and the partial ex ­cavation of the Waldhalde and Südwesthalde dumps. The Lokhalde dump will be completely excavated and removed by 2021.

Excavation of the Waldhalde dump began in July 2008. In an initial step the dump slope is flattened. For that purpose, dumped material is removed from bottom right up to the top. The excavated material is used for contouring the Cul mitzsch tailings manage­ment facilities. To date, some 1.9 million cubic metres of dumped material have been excavated from the Waldhalde dump and moved to the Cul mitzsch tail­ings management faci lities for contouring. Before contouring will be finalised by 2019, an additional volume of some 3.6 million cubic metres is slated for excavation and removal.

31

Seelingstädt water treatment plant (2004)

One slope of the Südwesthalde dump is also con­sidered to lack long­term stability in its present state. During the period 2014 –2016 it shall therefore be flat­tened by excavation and removal of material which will for the main part be used for building the final cover across the ponds of the Culmitzsch tailings management facilities.

Following completion of the measures aimed at enhancing slope stability and providing cover materi­als, forests will be restored on the Waldhalde and Süd ­westhalde dumps.

AreasSignificantly contaminated areas within the cleared plant premises of the Seelingstädt mill were rehabili­tated by soil replacement. A similar approach will be used at the cleared footprints of the Lokhalde, Wald­halde, and Südwesthalde dumps.

The excavated contaminated soil from plant area rehabilitation is used either as interim cover material or for contouring purposes at the Culmitzsch tailings management facility.

Remediation of the areas of the former plant premises is almost finalised; out of a total of 83 hec­tares, 70 hectares were reclaimed by the end of 2010. Completion of remaining work will take until 2017, because items up for demolition like the retention ponds, factory roads, parking spaces, and the railway

unloading facility will be needed up to that point to conduct final remedial operations.

Collection and treatment of contaminated waters Seepage collected by rows of wells and deep drains located around the Trünzig and Culmitzsch tailings management areas as well as the remaining superna­tant water from Culmitzsch A are merged in a storage and homogenisation lagoon and then pumped to the Seelingstädt water treatment plant.

At the beginning, supernatant water and seepage were treated in the former uranium ore processing facility at the Seelingstädt site. In 2000, a new water treatment plant was erected next to the Cul mitzsch tailings management facility; that plant went on stream in 2001. It has a design capacity of 300 cubic metres per hour and uses a lime precipitation flow sheet. Water treatment residues are immobilised and stored in an engineered disposal cell within the peri­meter of Culmitzsch B tailings management facility. The treated waters are discharged into the Cul mitzsch ­bach creek from where they get into the Weiße Elster River.

Since it came on stream, the new plant has treat­ed some 22 million cubic metres of contaminated waters from the Trünzig and Culmitzsch tailings management facilities. Investment expenditure for the construction of the Seelingstädt water treatment plant was in the order of 8 million euros.

Outlook

After completion of remedial operations, forests and green spaces established on the covered Trünzig and Culmitzsch tailings management facilities as well as the renatured plant premises and dump footprints will have to be managed, i.e. post­remedial care and maintenance will have to be provided. Further long­term tasks are water treatment and monitoring. See­page levels from the Trünzig and Culmitzsch tailings management facilities may drop over time; but the seepage flow will never dry up completely; and seep­age quality will not comply with standards for direct discharge into Culmitzschbach creek for an extended period of time. As a consequence, water treatment will have to be continued for a very long period of time.

32 4 Remediation sites

Crossen/Helmsdorf

Initial situation

The Crossen processing plant was established in 1950 on the premises of the Leonhardt paper factory. Pro­cessing of uranium ores ceased already at the end of 1989 for economic considerations.

Since the Zwickauer Mulde River was running right through the 21 hectares plant premises, the site was cut into two distinct areas. The 17 hectares area on the right bank of the Mulde River was densely built­up and comprised the factory buildings of the processing plant, while the ore discharge and storage facilities were on the left bank of the Mulde River.

The Crossen plant processed for the most part ores from mines in the Ore Mountains and from the Ronneburg district as well as – until 1960 – from open pit mines near Seelingstädt. Until 1980, wet chemical as well as radiometric sorting and gravity concentra­tion methods were used for ore processing. Later, only the hydrometallurgical process was used. In total, some 74 million tonnes of ore were milled and 77,000 tonnes of uranium produced in Crossen.

Residues of the hydrometallurgical process were

disposed as slurries in the Helmsdorf, Dänkritz I and

Crossen ore processing plant (1991)

Dänkritz II tailings management facilities. The 3 tail­ings management facilities cover a total area of some 227 hectares and contain approximately 57 million cubic metres of tailings (Table 4).

The Helmsdorf tailings management facility was established by the damming of two valley locations. It was operational from 1958 to the shutdown of ore processing in 1989.

The Dänkritz I and Dänkritz II tailings manage­ment facilities were established in the early 1950ies at the site of two abandoned gravel pits located north of the Helmsdorf tailings management facility. When the latter was commissioned in 1958 the two Dänkritz sites were closed. In 1990, the Dänkritz II tailings management facility was no longer owned by the Wismut GmbH and it is not part of the company’s remediation mandate.

The discarded waste rock from the radiometric and gravitational ore processing was dumped on the Crossen waste rock pile. At the time when production was terminated, some 3.2 million cubic metres of resi­dues had accumulated on an area of 22 hectares, in ­cluding ca. 0.5 million cubic metres of tailings from hydrometallurgical processing during the early years of operation until 1952.

33

Remediation goals/concepts

Remediation of the legacies left behind at the Crossen site was implemented on the basis of the subsequent concepts:

3Plant Facilities and Buildings: complete dis­mantling and demolition of all structures.

3 Helmsdorf and Dänkritz I Tailings Mana ge­ment Facilities: Removal of supernatant water, followed by interim cover building, contouring and final covering of the tailings; vegetating for erosion protection and afforestation of covered tailings areas.

3Crossen Waste Rock Pile: Complete relocation to the Helmsdorf tailings management facility and use of the waste rock for interim cover and contouring purposes.

Helmsdorf Dänkritz I Dänkritz II Total

Tailings area ha 200 20 7 227

water covered ha 116 12 3 131

Volume supernatant water 106 m3 5 0.25 0.05 5.3

Tailings volume 106 m3 45 5 1 50

Solids 106 t 50 7 1 58

Maximum Tailings thickness m 55 23 19

Maximum Water depth m 14 2 2

Table 4: Parameters of Helmsdorf and Dänkritz tailings management areas (1990)

3 Operation Areas: Rehabilitation of the former plant premises and of the Crossen waste rock pile footprint, design as alluvial landscape and flood retention area.

3Contaminated Waters: Treatment of contami­nated supernatant waters and of seepage collect­ed near tailings management facilities in the Helmsdorf water treatment plant. Seepage treat­ment to be continued until compliance with dis­charge standards.

Remediation achievements

Plant facilities and buildings19th century buildings beyond repair, any reuse was ruled out from the outset. Therefore, facilities and buildings were completely demolished.

Remediated Crossen plant area with waste rock pile removal in progress (2008)

34 4 Remediation sites

Dismantling of some technical equipment had begun as early as 1989. Dismantling and demolition of large and sophisticated equipment was contracted to specialised firms. Dismantling and demolition of all above ground buildings and facilities was accom­plished by 2006.

Dismantling and demolition work generated

26,500 tonnes of scrap and 62,300 cubic metres of demolition rubble; of that total, 21,000 tonnes and 49,000 cubic metres, respectively, were contaminated. Radioactively or chemically contaminated scrap and demolition rubble were first dumped at the Crossen waste rock pile for interim storage and subsequently moved to the Helmsdorf tailings management facility. At Helmsdorf the rubble was used for interim covering purposes and the scrap was disposed in engineered cells within the covered tailings beach areas. Un ­contaminated scrap was sold, the rubble for the most part used for roadwork on site.

Helmsdorf and Dänkritz I tailings management facilitiesIn order to mitigate immediate risks, interim action undertaken immediately after termination of produc­tion focused on covering exposed sandy tailings to prevent windblown dust. Moreover, seepage collec­tion systems were extended.

Remediation work in the proper sense began in 1996 after commissioning of the new water treatment plant at the Helmsdorf site, where the pumped away supernatant water could be treated and hence the water level in the Helmsdorf tailings facility could be gradually lowered. During the following years the ex ­posed tailings areas were capped with an interim cover.

By the end of 2010, some 201 hectares had been capped with 1.5 metre interim cover; this effort had consumed 2.9 million cubic metres of waste rock and sand and gravel, respectively. The interim cover is now 98 per cent complete, with a small residual lake remaining atop the pond’s deepest point.

Work began in 2002 at the Helmsdorf tailings

ma nagement facility to establish a final contour de ­signed as an undulating landscape of hills and swales. This involves the slope flattening and partial excava­tion of embankment dams. The material removed this way together with mineral soil from nearby bor­row pits is used to shape the hills of the plateau area. Since 2005, the contoured areas are in the process of being capped with a final cover of 1.5 metre of miner­al soil. The plateau relief is designed to allow dis­charge of surface run­off to wards the Wüster Grund dam and towards Ober rothen bach. A minor portion of the run­off will discharge towards the Zinnbach creek, just like the run­off from the Dänkritz I tailings

Helmsdorf and Dänkritz I tailings management facilities, Crossen site (2010)

35

management facility where contouring and cover placement were finalised in 2007.

Contouring and final cover placement at the Helmsdorf and Dänkritz I sites are to be finalised by 2017. Some 6 million cubic metres of material have been used for this purpose to date. An additional vol­ume of 3 million cubic metres will be required to complete the task.

The reclaimed area shall be used for forestry and grassland purposes.

Crossen waste rock pileThe Crossen waste rock pile has already been relocat­ed to the Helmsdorf/Dänkritz I tailings management facility at nearly 85 per cent. Excavation of the re ­maining waste rock material and of the soil from foot­print remediation is to be terminated by 2015.

Since 1997, haulage of waste rock and crushed de ­

molition rubble to the Helmsdorf tailings management facility is conducted by pipe conveyor over a distance of 1.8 kilometres, which minimises environmental impacts as opposed to truck haulage on public roads.

AreasInitiated in 2003, remediation of plant premises of the former Crossen uranium ore processing unit was completed by 2008. Contaminated soil was excavated and replaced by unpolluted earthen materials. Gen­erated as a result of remediation work were 294,000

cubic metres of contaminated fill and excavated soil, 115,000 cubic metres of contaminated demolition rubble, and more than 3,000 cubic metres of multiple contaminated materials. On balance, nearly 268,000 cubic metres of uncontaminated soil materials were needed as replacement. The area is now vegetated and blends in with the floodplain landscape of the Zwickauer Mulde River.

Following removal of contaminations identified in the ground, the 22 hectares footprint of the Crossen waste rock pile, located immediately along the Zwickauer Mulde River, is to be turned into green space and shall serve as a polder for flood control. Remediation of the footprint and dismantling of the pipe conveyor are to be completed by 2016.

Collection and treatment of contaminated watersUntil 1995, supernatant water and seepage were treated in an existing treatment plant at the Crossen site. In 1995, the Helmsdorf water treatment plant was the first of the state­of­the­art treatment plants of Wismut GmbH to come on steam. The plant had a design capacity of 250 cubic metres per hour. In the early years, it used a highly complex process to remove uranium, radium, and nonradioactive contaminants separately from supernatant and seepage waters. Treatment sludges were immobilised separately and disposed at a licensed location within the Helmsdorf tailings management facility. In order to simplify the process and for cost reasons, precipitation with lime

Pipe Conveyor, Crossen site (1996)

36 4 Remediation sites

was introduced in 2002. Presently, the two­line facili­ty has a design capacity of 200 cubic metres per hour. Immobilised residue sludges continue to be disposed at the Helmsdorf tailings management facility. Treated waters are discharged to the Zwickauer Mulde River.

Construction costs for the Helmsdorf water treat­ment plant were in the order of some 20 million euros. Since it came on steam, the Helmsdorf water treatment plant has processed some 21 million cubic metres of contaminated supernatant and seepage water from the Helmsdorf and Dänkritz I tailings management facilities.

Outlook

After completion of remedial operations, the covered areas of the Helmsdorf and Dänkritz I tailings man­agement facilities which will be used for the most part for silvicultural purposes, will have to be managed, i.e. post­remedial care and maintenance will have to be provided. Further long­term tasks are water treat­ment and monitoring. Seepage from the Helmsdorf and Dänkritz I tailings management facilities may drop over time, but the seepage flow will never dry up completely, and seepage quality will not comply with standards for direct discharge into the Zwickauer Mulde River for an extended period of time. As a con­sequence, water treatment will have to be continued for a very long period of time.

Königstein

Initial situation

Prospecting for uranium in Upper Cretaceous sand­stones of the Elbe rift valley southeast of Dresden began in the early 1960s. In 1963, the Königstein de ­posit was discovered. Mine development commenced as early as 1964 and eventually comprised 5 pit shafts and 7 ventilation raises as well as headings, extraction drifts, and cross­cuts on 4 levels. The surface area af ­fected by mining operations extends over ca. 6 square kilometres near the localities of Königstein, Bielatal, Langenhennersdorf and Struppen.

Systematic operations were undertaken in 1967

using conventional underground mining methods.

A total rock volume of some 9 million cubic metres including about 5 million cubic metres of ore were mined by conventional mining. The ore was hauled by ropeway to the Rottwerndorf loading station and then by rail to the central ore processing facility at Seelingstädt. Waste rock from mine development and conventional ore mining was moved to the Schüssel­grund mine dump.

Following development of an in situ leach techno­logy, the mine shifted to full in situ leaching of urani­um in 1984 as a response to decreasing uranium grades.

Königstein plant area (1994)

37

Leaching of the ore was performed with ground­water to which sulphuric acid had been added. By 1990, more than 55 million tons of sandstone had come into contact with the leach liquor. When min­ing was terminated, a portion of the liquor remained locked in the sandstone as pore water. Uranium was also extracted at 8 on­site leach pads from the ore that had been removed from underground in order to prepare for the in situ leach operation. Pregnant liq­uor from underground leaching and from the heap leach operation was piped to an above ground ion exchange unit which produced a liquid uranium con­centrate as an interim product for final processing at Seelingstädt. Residues from this process as well as the leached rock were moved to the Schüsselgrundhalde mine dump.

When uranium production was terminated in 1990, the mine had produced about 18,000 tonnes of uranium, of that total some 70 per cent by conven­tional mining and 30 per cent by in situ leaching.

Remediation goals/concepts

Its location within the Sächsische Schweiz Protected Landscape Area and its vicinity to the Elbe River make the Königstein site stand out among the other reme­diation sites of Wismut GmbH.

Above ground remediation is characterised by the requirement to blend the area affected by mining into the „Sächsische Schweiz“ Protected Landscape Area and to control contaminant release from above ground springs and wells. The remedial concept speci fies in this respect that radioactively contami­nated facilities and buildings unfit for further use be demolished and radioactive areas excavated. In addi­tion to contaminated material from ground excava­tion, water treatment residues are to be moved to the Schüsselgrund mine dump.

Clean­up goals for the Schüsselgrund mine dump focus for the most part on the reduction of precipita­tion infiltration into groundwater, of radon exhala­tion and of gamma radiation exposure. To this end, the mine dump is recontoured and capped. Capping will be followed by vegetation as the final step to inte­grate the dump in the Protected Landscape Area.

In addition to the requirement of remediating and cleaning up the above ground legacies such as ore handling grounds, heap leach pads, buildings, plant areas, and the Schüsselgrund mine dump, the task to minimise contaminant release in the wake of flooding the mine workings presents an enormous challenge.

The mine flooding concept was based on the awareness that flooding immediately after mine shut­down would entail high environmental risks. Un con­trolled flooding of the mine would have allowed the residual uranium and other metals to dissolve and rise from the deposit located in the fourth aquifer to the overlying third aquifer and then discharge to the Elbe River.

With this scenario in mind, the option calling for monitored and controlled flooding involving con­struction of control drifts and water treatment in an above ground facility was given preference over all other remedial approaches. Therefore, remedial emphasis will focus on:

3 Removal from underground of substances with the potential to pollute the incoming groundwa­ter (grease, oil, etc.),

3 Operation of control drifts aimed at preventing discharge of contaminated water, and allowing direct monitoring and sampling of flood water,

3 Attenuation of sulphuric acid concentration of leach solutions,

3 Removal of easily soluble uranium and other heavy metals, and

3 Sealing of mine perforations between the 3rd and 4th aquifer to minimise water rise into 3rd aquifer during flooding.

Remediation achievements

While the slope of the Schüsselgrund mine dump is already capped with 1 metre of mineral soil to reduce radon exhalation and infiltration of precipitation as well as to promote vegetation, precipitation contin­

38 4 Remediation sites

ues to infiltrate the mine dump by the uncapped pla­teau area. Contaminated seepage is intercepted by a drainage system and piped to the flood water treat­ment unit. A rainwater retention pond established at the toe of the mine dump receives uncontaminated

run­off from reclaimed slope areas for discharge to the receiving stream.

The Schüsselgrund mine dump will continue to receive any radioactively contaminated material

Königstein mine, schematic vertical profile, flood level as of December, 2010 (not to scale)

Shaft 398

South North

135 m level

94 m level

50 m

S a n d s t o n e

Aquitard

Aquitard

Aquitard

Flooding 2010: 102 m NN

25 m level, north controll drift

Flooded mine,

aquifer no 4

G r a n i t e

North fault

Shafts 388 and 390

Air well no. 5

Dewatering wells

Aquifer no. 1Aquifer no. 2Aquifer no. 3

level

39

from the clean­up of the Königstein site. In 2009 alka­line material was tilled into the top layer of the entire uncapped plateau area. Precipitation is supposed to take up and carry the alkalinity inside the dump and aid in the neutralization of the dump’s acidic pore water. The final covering of the Schüsselgrund mine dump started in 2010.

In the meantime, off­site plant areas like the Rott­werndorf ore loading station have been cleaned up.

Establishment of underground control drifts

designed to intercept contaminated flood water was finalised in 1994. After experimental flooding con­ducted over several years, flooding of the Königstein mine was initiated in 2001. Since then, natural inflow and controlled addition of groundwater have gradu­ally raised the water level in the mine to ca. 100 me ­tres a.s.l.

To continue flood control after mine closure, it was necessary to connect the flooded control drifts which are then functioning as horizontal wells to the water treatment plant. To this end, two 300 metres deep wells were drilled in 2009 at a cost totalling about 8 million euros.

While the underground mine was prepared for

flooding, a water treatment plant was built to treat

contaminated mine water. Investment expenditure for this two­stage unit for uranium removal and water treatment was in the order of ca. 15 million euros. Since coming on­stream in 2000 the plant has treated 39 million cubic metres contaminated water.

Impacts due to remedial operations are recorded and documented as part of the environmental moni­toring programme. Environmental surveillance at the Königstein site comprises long­term monitoring of flood water and mine dump as potential sources of contaminant release and of their impact on ground­water and surface water bodies. Moreover, a flood­related monitoring system was established to moni­tor and control the flood process. Monitoring also extends to the release of airborne particles.

Concentration levels of trace elements and urani­um in the flood water have significantly decreased as a result of the multi­year flushing of the sandstone in the underground mine. Immission measurements conducted in the Elbe River show that there is no environmentally relevant impact on the Elbe due to discharge of treated water from the Königstein site.

The flood monitoring network monitors the rise of the groundwater level in the third and fourth aqui­fer, the void subject to flooding, and the groundwater quality during and after flooding of the Königstein

Plant area and Schüsselgrund mine dump (2007) Remedial work at Schüsselgrund mine dump (2010)

40 4 Remediation sites

mine. Monitoring emphasis is on areas of zones of potential flood water rise to the third aquifer as well as on discharge areas of the third and fourth aquifer along the northern and western edges of the mine.

Due to the continued shrinking of the volume of open mine workings in recent years, there is a steady decrease of radon exhalation from the Königstein mine. There is no record of any significant radiologi­cal exposure to the public via the atmospheric path­way.

Outlook

In preparing for further pull­out of the mine, gradual backfilling of pit shaft #390 continues. Sealing of the last remaining ventilation raise #5 is under way and the open drift in the aquiclude is being backfilled. According to current planning, pull­out of the mine is to be finalised by mid­2012 after sealing of pit shafts #388 and #390.

The licensing procedure initiated in 2005 for final flooding up to the natural level of groundwater rise is currently suspended.

Dresden-Gittersee

Initial situation

The Dresden­Gittersee site of Wismut is located with­in a historic coal mining district where hard coal was mined from 1542 through 1967. After the uranium content of the coal had been established in 1946, coal was also mined for its uranium content from 1947 till 1955. In the 1950s, Wismut temporarily took over hard coal mining operations from VEB Steinkohlen­werk Freital, later renamed as VEB Steinkohlenwerk “Willi Agatz”. Following complete taking over by Wismut in 1968, the uranium­bearing coal deposit was exclusively mined for uranium.

The uranium deposit extends across the mining fields of Gittersee, Bannewitz, and Heidenschanze. Abandoned in 1958, the Heidenschanze mining field was not included into uranium mining operations starting in 1968 for economic reasons, but remained hydraulically connected to the other mining fields.

The mined uranium­bearing coal was at first

hauled to Freital­Döhlen and Dresden­Coschütz for

Groundwater sampling at Königstein site

41

processing. Afterwards, the ore was transported by rail to Crossen or Seelingstädt, respectively, for processing.

When mining operations were terminated in 1989, about 4 million tonnes of uranium­bearing coal had been mined, creating mine workings of some 2 million cubic metres and extending over a surface area of 210 hectares. A considerable portion of the mine workings has either caved or was closed by set­tlement. From 1949 through 1989 about 3,700 tonnes of uranium were produced.

Remediation goals/concepts

Remediation and clean­up work began shortly after mining was terminated in 1990. This work was based on preliminary studies conducted already in 1988 on mine workings rehabilitation. Termination of mining operations was followed by a systematic recording of contaminated areas, investigations of the hydrogeo­logical regime, of groundwater quality in the vicinity of plant areas and mine dumps as well as the sam­pling of receiving streams.

In line with the results and findings of those pre­liminary activities, the proposed rehabilitation work called for the demolition and dismantlement of above ground facilities and buildings, clean­up of areas con­

taminated by the mining of uranium ore as well as the remediation in situ of the Gittersee and Marien­schacht mine dumps by contouring and capping with a multiple layer cover.

Proposed work for underground remediation included the rehabilitation of the mine workings by backfilling of pit shafts and controlled flooding of the mine workings. The flooding conception provided for the flood water to rise within the mine workings and be kept at a safe level from where it would discharge via the Tiefer Elbstolln tunnel to the Elbe River.

Preparations for flooding included:

3Removal from the mine workings of materials with the potential to pollute the incoming water, and in particular of hydrocarbons,

3Backfilling and safe plugging of pit shafts,

3Extension of the monitoring network between the Gittersee mine and the Tiefer Elbstolln tunnel to monitor flooding,

3Rehabilitation of the Tiefer Elbstolln tunnel which was built from 1817 to 1837 to dewater the 19th century coal mines but had lost a considerable

Plant area Dresden­Gittersee before remediation (1992)

42 4 Remediation sites

portion of its hydraulic efficiency by 1.5 metre sludge deposition,

3Establishment of an alternative temporary water handling system by sinking a drainage well at each of the Gittersee/Bannewitz and Heiden­schanze mining fields to provide for the case that insufficient flood water drainage via the Tiefer Elbstolln tunnel would require the construction of a water adit between the Gittersee mine and the Tiefer Elbstolln tunnel.

Remediation achievements

Except for some minor residual work, remedial work performed on the plant area was finalised with the demolition of buildings and facilities and excavation of contaminated ground on an area of approximately 21 hectares.

Excavated contaminated ground and demolition debris have been incorporated in the Marienschacht and Gittersee mine dumps. Remediation of the Marienschacht mine dump including plant area was completed in 1999. Remedial work comprised place­ment of a multiple layer cover and grass seeding of the entire surface area. The Marienschacht pit and its Malakoff head frame form an industrial monument. Together with its associated mine dump it constitutes

a mining heritage ensemble. It currently houses the headquarters of Bergsicherung (Mine safety consult­ants) Freital.

The Gittersee mine dump was also rehabilitated

in situ. Its capping with a multiple layer system was finalised in 2006.

Natural discharge of the rising groundwater via the abandoned coal mines towards the Tiefer Elb­stolln tunnel was less than predicted and required. As a result, the water level rose up to 180 metres a.s.l. This level of flood water rise caused surface damage as well as surface water emergences in residential areas of the town of Freital. As a consequence, the flood level was lowered by discharge via the discharge well provided for such an emergency. The flood water level in the Gittersee/Bannewitz mining field is kept at ca. 115 metres a.s.l. Water discharged at the Gitter­see/Bannewitz mining field is treated in the water treatment plant located on the Gittersee mine dump and discharged in the Kaitzbach creek. Water treat­ment residues are incorporated in the Schüsselgrund mine dump at the Königstein site.

In order to preclude renewed flood water rise and subsidence risks, the decision was taken in 2005, fol­lowing regulatory approval, to develop a horizontal gallery running between the Tiefer Elbstolln tunnel

Remediated plant area and mine dump at Dresden­Gittersee site (2007)

43

and the Gittersee/Bannewitz mine over a total dis­tance of ca. 2,900 metres. Flood water from the Gittersee/Bannewitz and Heidenschanze mining fields is to discharge via this gallery to the Tiefer Elbstolln tunnel and from there to the Elbe River without any risk to the public. Flood levels in the Gittersee mining field will be constantly kept at ca. 120 metres a.s.l. and in the Heidenschanze mining field at ca. 130 metres a.s.l.

Development of what is known as Wismut gallery began in 2007 in Freital­Potschappel at the site of the abandoned Osterberg quarry. From that point, the gallery is being developed to the northwest in the direction of the Tiefer Elbstolln tunnel and to the southeast in the direction of pit shaft #3 of the Gitter­see mining field located in Freital­Burgk.

Rock anchoring, bolting, meshing, and grouting were required to ensure safety and long­term stability in heavily fissured and water­bearing rock zones. By the end of 2010, development progress was 915 metres towards northwest and 321 metres towards southeast.

Pending completion of the Wismut gallery in

2013, the flood water level in the abandoned Dresden­Gittersee mine is kept at ca. 115 metres a.s.l. Prior to discharge to the receiving stream, pumped flood waters are treated with lime slurry in order to reduce iron levels. Heavy metals, on the contrary, are only present at very low concentration levels and there­fore are not of environmental relevance.

Outlook

It is a specific feature of the Dresden­Gittersee site that there are no waters with radionuclide levels requiring licensing under radiation protection legis­lation for discharge into receiving streams. Perma­nent safe discharge of waters from the flooded Dres­den­Gittersee mine via the Wismut gallery towards the Tiefen Elbstolln tunnel will make pumping, treat­

Development work of Wismut­Stolln, Dresden­Gittersee site (2009)

Marienschacht mine dump, Malakoff tower, Dresden­Gittersee site (2009)

44 4 Remediation sites

ment and discharge of flood water into the Kaitzbach creek redundant. The water treatment plant can therefore be dismantled upon completion of the gal­lery. In addition to mitigating environmental impacts, the development of the Wismut gallery will also have cost­saving aspects.

Schlema

Initial situation

The Schlema site is located in southwest Saxony, immediately north of the town of Aue. At this site, one of the world’s largest “hydrothermal” uranium depos­its was mined from 1946 through 1990, with its lodes yielding ca. 80,000 tonnes of uranium. Mining opera­tions affected areas within the townships of Ober­schlema and Niederschlema as well as in the Aue sub­urb of Alberoda and extended to the boundaries of the towns of Schneeberg and Hartenstein.

Uranium ore mining in the Schneeberg­Schlema­Alberoda ore field followed upon mining operations for tin, iron, silver, bismuth, copper, cobalt, and nick­el which have taken place in this district since the mid­15th century. Since the 19th century, uranium was mined as a by­product. This advance knowledge of uranium occurrence and of the use of radon­laden water in the Oberschlema spa launched prospecting

for uranium in this area in 1945. Investigations began in the region of Oberschlema at the site of the Markus­Semmler­Stolln, a drainage gallery built in the 16th century in order to dewater the historic Oberschlema und Schneeberg mines. The gallery runs from the portal at the Zwickauer Mulde River along the entire Schlema valley and extends out under Schneeberg right up to Wolfgangmassen.

In 1946, near­surface mining started at numerous newly discovered lodes in the Oberschlema area. The subsequent development of the deposit down to a depth of 640 metres involved 30 pit shafts as well as several adits, blind shafts, and winzes. The Markus­Semmler­Stolln gallery was defined as 0­metre­level for surveying purposes. The horizontal development of the Oberschlema deposit comprised a total of 23 levels.

During the course of mining operations, an

extended waste pile landscape emerged at the site of the historic Oberschlema radon spa. Apart from waste rock dumped right in the town’s centre, a number of conical waste rock piles disturbed the local scenery. Mining operations also extended to the Silberbach valley and the Hammerberg. In an effort to redress the lack of dumping grounds available in the town area, a rail track was built to haul waste rock for dumping along the Hammerberg and Schafberg slopes. In the end, waste rock dumping was extended

Schlema (1960)

45

to the Borbachtal valley located within the boundary of the Wildbach community.

By the late 1950s at the latest, the Oberschlema deposit was exhausted. Abandoned pit shafts were for the most part backfilled with waste rock and to some extent subsequently plugged. Surface subsidence as well as near­surface mine voids were locally back­filled, but there was no systematic mine rehabilita­tion. As mining­induced surface cave­ins and subsid­ence continued to occur, larger portions of the Oberschlema town area had to be fenced off and which subsequently degenerated into wasteland.

With the discovery of the larger and more fertile Niederschlema­Alberoda deposit, mining operations shifted to the lower Schlema valley and to the banks of the Zwickauer Mulde River. Mining in that district went down 1,800 metres below the level of the Markus­Semmler­Stolln gallery. In the wake of these mining operations, large waste rock pile complexes were dumped on both sides of the Zwickauer Mulde River and along the town boundaries.

Physical processing of the mined uranium ore was initially conducted in the Blue Colour Factory at

Oberschlema with residues being discharged into the newly established settling pond in the Borbach valley. From the mid­1950s, radiometric sorting was con­ducted at pit shaft #371 and hydrometallurgical pro­cessing at the Crossen processing plant.

In the1960s during active mining, pilot­scale pro­jects were initiated with a view to conducting pur­poseful remediation of the waste rock piles involving contouring and afforestation. This, however, resulted only in modest corrections to the waste rock pile land­scape.

In the end, mining operations extended over an area of ca. 22 square kilometres and had created underground mine openings on 62 levels with a total mined volume of ca. 41 million cubic metres that had been developed by means of more than 54 pit shafts, numerous blind shafts, and a couple of adits. Of that total, 8 pit shafts including 4 ventilation shafts, and 10 blind shafts were still in operation after mine shut­down. Horizontal headings totalled 4,200 kilometres. When remedial work started, 176 kilometres of head­ings on 7 levels were still accessible. Mining waste totalling ca. 45 million cubic metres had been dumped on 42 waste rock piles covering an area of 311 hectares.

Waste Rock Pile Footprintha

Volume106 m3

End of Remediation* Year

Dump pit shaft 38 alt/Lichtloch 9 7 0.54 2007

Dump pit shaft 38 neu/208 26 4.7 2012

Dump pit shaft 13b 5 0.27 2007

Hammerberghalde waste rock pile 43 4.0 2011

Dump pit shaft 66/207 25 4.1 2018

Dump pit shaft 371 67 13.5 2025

Dump pit shaft 310 5 0.57 2024

Dump pit shaft 366/plant areas 186/366/383 42 7.7 2013

Dump pit shaft 208W 2 0.06 2001

Dump pit shaft 8 2 0.06 1998

Dump + plant areas pit shaft 12/259/309 14 1.9 2022

Dump Blue Colour Works/pit shaft 13 1 0.04 2008

Dump + plant area pit shaft 373 1 0.11 2007

Dump pit shaft 382 34 4.2 2018

Dump Großschurf I/plant area timber storage 250 2 0.03 1999

Dump pit shaft 372 2 0.08 2008

Dump 312 14 1.2 2011

Dump 382West 26 3.2 2016

Dump pit shaft 250 5 1.0 1992

* including 5 years post-remediation

Table 5: Waste rock pile remediation at Schlema site

46 4 Remediation sites

Wismut GmbH has responsibility for the reclamation of 19 of these waste rock piles.

The plant areas associated with the Aue mining unit extended over 111 hectares. Apart from mine pits, mine support and auxiliary units included repair shops, storage and supply complexes, the radiometric sorting unit, ore loading facilities, and tailings pond in the Borbach valley. Handling of uranium ores had caused widespread radioactive contamination of plant areas and technical facilities as well as locally elevated levels of arsenic and heavy metals.

Remediation goals/concepts

The remediation objectives were as follows:

3 Removal of technical substances with the poten­tial to pollute incoming groundwater, followed by mine flooding and adjustment of mine ventilation to rising flood water levels,

3 Erection and operation of water treatment plants to reduce contaminant levels in mine waters prior to discharge into receiving streams, and

3 Protection of ground surface against subsidence events by backfilling of near­surface mine voids.

Above ground remedial action was aimed at restor­ing to profitable reuse the areas affected by uranium mining operations.

In detail, the above ground remediation pro­gramme was focussed on the following activities:

3Remediation of waste rock piles and preparation for their gradual return to profitable use on the basis of agreed reuse concepts,

3Demolition and dismantling of buildings and facilities unfit for future use, and

3Rehabilitation of plant areas.

In essence, the remediation concept for the waste rock piles provided for their rehabilitation in situ including regrading for long­term stability as well as capping and vegetation.

Remediation achievements

By the end of 2010, 45 pit shafts had been backfilled, sealed, and plugged to ensure long­term stability. In order to protect the ground surface against subsid­ence, 232.000 cubic metres of near­surface mine voids were backfilled in the Schlema­Alberoda area. A major remedial focus was the safeguarding and back­

Schlema subsidence area, spa park (1960)

47

filling in a large subsidence area in Oberschlema, turned into a spa park. Another important task was the establishment of stable and long­lasting mine ventilation. For this purpose mine workings on the Markus­Semmler level were upgraded and the venti­lation shaft #382 was equipped with new mine fans.

Flooding of the mine began as early as 1991. To date, ca. 99 per cent of the floodable mine workings are flooded. The residual void of ca. 0.5 million cubic metres remaining below the Markus­Semmler level will be used as buffer storage facility to compensate for peak inflow levels or temporary shutdown of the water treatment plant. The plant which was built at a cost of 15 million euros has since start­up in 1998 treated some 13 million cubic metres contaminated mine water.

Operation of the water treatment plant will per­manently ensure that no contaminated flood water will emerge. The flood water level may be lowered or raised as need may be. Residues from the water treat­ment will be moved to waste rock pile #371 where they are incorporated and covered. Seepage from waste rock pile #371 is treated in a facility erected in 2009 and then piped to the Zwickauer Mulde River just like the treated flood water.

In the immediate vicinity of Oberschlema and in Alberoda, the waste rock pile landscape is completely recultivated. Remedial work is still underway at the sites of waste rock piles #309, #310, and #371. At the other waste rock piles, substantial remedial work is to a very large extent finalised. At these sites care, post­remedial maintenance and long­term tasks are per­formed in order to ensure long­term remedial suc­cess. Focus is on grass mowing and grazing, mainte­nance of ditches and culverts, and forest tending.

In the vicinity of waste rock piles, remedial pro­gress is significantly reflected by diminished radon concentrations in ambient air. Many sites have reached compliance with radiation protection standards. At some locations work is continuing to further improve the situation.

Surveying and geomechanical monitoring pro­vides evidence of flooding­induced ground move­ments which, however, are negligible in comparison to mining­induced movements.

Outlook

Underground remedial work still to be accomplished will focus on the Markus­Semmler level in the Ober­schlema mining field where further refurbishing of

Bad Schlema spa area (2008)

48 4 Remediation sites

drifts is required to complete the establishment of a stable and long­lasting mine ventilation. What is more, a deformed section of the Markus­Semmler water­adit which is not safe for operation in the long run will have to be replaced. In its place a new by­pass adit (aka Südumbruch) of 1,200 metres length is to be developed from 2011 to 2013.

As a constant drop of contaminant levels in the

flood water is to be expected but will take some time

to reach compliance standards, operation of the water treatment plant will have to continue for an extended period of time.

Focus of waste pile remediation during forthcom­ing years will be on waste rock complex #371 where integration of contaminated soil and rubble from area rehabilitation and demolition of buildings as well as of immobilised water treatment residues will continue. Cover building operations will be finalised

Waste rock pile #38neu / #208, pit shaft #382 and Borbachtal settling pond, (1992)

Pit shaft #366, waste rock pile #366 (1991)

49

Waste rock pile # 366, conclusion of remedial work (2010)

Waste rock pile #38neu /#208, pit shaft#382 and covered Borbachtal settling pond (2010)

by 2016 except for the engineered area where immo­bilised residues are to be integrated.

Final contouring and capping of the remaining remotely located waste rock piles #309 and #310 are to be completed by 2015. Depending on remedial pro­gress, follow­up work on the reclaimed areas will include care as well as post­remedial and long­term tasks. These works are required to ensure long­term remedial success.

Pöhla

Initial situation

The Pöhla site is located in the Western Ore Moun­tains on the border with the Czech Republic. The sur­roundings of Pöhla contain many traces of historical mining; some of them date back to the 17th century. After 1945 Wismut started a number of mining devel­opments in the area. Uranium mining conducted in

50 4 Remediation sites

the Pöhla area from 1967 through 1990 produced about 1,200 tonnes of uranium.

During prospecting for uranium mineralisation the Hämmerlein tin deposit and the Tellerhäuser tin­uranium deposit were developed by the Pöhla adit and vertical passageways. Mining operations created the spacious mine void of ca. 1 million cubic metres of the Pöhla mine. The adit portal was annexed to a vast plant area which included the Luchsbachhalde mine dump. A radiometric ore sorting unit was erected at this site during the 1980s, but shutdown after trial operation. As a consequence, the ore mined from the Pöhla­Tellerhäuser deposit was trucked to the sorting unit at mine shaft #371 of the Aue mining unit.

The smaller, separate Pöhla­Globenstein mine

had been developed by prospect shaft #24 sunk as early as 1957. Despite most intense prospecting on three levels no mineable uranium mineralisation was detected. In 1989/90, the pit shaft was partly back­filled to ground level and plugged, and the mine was flooded.

On balance, the mining field extended over an area of about 5.5 square kilometres. Above ground units and the associated pit openings, buildings, facil­ities, and mine dumps covered an area of 60 hectares. Of that total, the 4 mine dumps covered a footprint

area of ca. 34 hectares. Their volume was about 2 mil­lion cubic metres.

Remediation goals/concepts

The following works had to be accomplished in order to ensure a sustainable reduction of contaminant release from the mine closed in 1990 and to blend the reclaimed former mining area into the surrounding landscape:

3Removal from underground of technical sub­stances with the potential to pollute the incom­ing water,

3Backfilling of redundant near­surface vertical passageways and of adits, except for the main adit,

3Flooding of the mine until natural overflow occurs at the level of the main adit,

3Maintenance of the main adit to allow monitor­ing and discharge of contaminated flood water separately from unpolluted infiltration water on the one hand and to maintain access to mine voids for the storage of residues of the Pöhla water treatment plant, on the other,

Plant facilities Pöhla (1991)

51

3Erection and operation of a water treatment plant for flood water, and

3Remediation of mine dumps the largest of which was the Luchsbachhalde dump containing 1.8 million cubic metres of mine waste and covering an area of 26 hectares.

Remediation achievements

All above ground facilities were either dismantled or demolished. The Luchsbachhalde dump was regrad­ed and capped with mineral soil. Construction of for­est roads and drainage ditches as well as landscaping was terminated on and around the Luchsbachhalde mine dump in 2008, ending substantial remediation work in this area.

After termination of clean­up and demolition work in the Tellerhäuser area, flooding of the mine commenced in 1992. Until 2004, the flood water was kept below overflow level by pumping and piped to a water treatment plant built in 1994 at a cost of ca. 2 million euros where it was treated for its radium, arsenic, iron, and temporarily for its uranium levels.

Treatment residues from the water treatment plant were stored in the Hämmer lein section of the

Luchsbachhalde mine dump and passive­biological water treatment plant (2010)

Pöhla mine. A total of ca. 740 cubic metres of residues contained in 2,956 drums were moved underground for long­term safe storage using 1,700 cubic metres of concrete.

The scheduled overflow of flood water in 2004 coincided with the trial operation of a passive biologi­cal treatment plant which had been built at a cost of ca. 0.7 million euros. The treatment process includes self­aeration of the feed water followed by an iron hydroxide precipitation stage where arsenic is also re moved. In a following process stage radium is re ­moved by stonewort algae (Characeae). The final stage of the process chain consists of a series of filters designed to adsorptively remove residual arsenic and radium by means of reactive materials. During the trial operation it has become clear, however, that the biological process stage did not perform as anticipat­ed. With the process stages of iron hydroxide precipi­tation and filtration water treatment continues to comply with required standards. The contaminant­laden filter material is immobilised at the Schlema­Alberoda water treatment plant and subsequently integrated into the engineered cell of waste rock pile #371. Technologically modified and highly automat­ed, the water treatment plant is to return on stream by 2012.

52 4 Remediation sites

Outlook

Rehabilitation of the Luchsbachhalde mine dump, of the Pöhla plant area and of the Schurf 24 mine dump is finalised. Post­remedial care and environmental monitoring have to be continued at these objects.

Final rehabilitation of the Pöhla mine will only be

possible after water treatment is terminated. Given that flood water quality is improving at a very slow rate treatment will required over an extended period of time.

Remediated Luchsbachhalde mine dump (2010)

53

These areas and facilities used for uranium mining operations by the predecessor Wismut Company had been returned for the most part in an unremediated state to local authorities or private parties in the early 1960s. For these legacies which are known as formerly abandoned Wismut sites Wismut GmbH has no reme­diation obligations under the provisions of the Wismut Act as these sites were neither property of Wismut GmbH on June 30th, 1990 nor ceded to the company for unlimited and unrestricted use. A survey of these objects was established by the legacy inventory com­piled by the Federal Office for Radiation Protection on behalf of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. This inven­tory documented a total area of ca. 1,500 square kilo­metre in Saxony, Saxony­Anhalt, and Thuringia. For Saxony alone, ca. 1,900 individual objects were identi­fied. This inventory served as the basis for an initial agreement concluded in 2001 between the federal government and the Free State of Saxony regarding seven priority rehabilitation projects at the sites of Johanngeorgenstadt, Breitenbrunn and their envi­ronments. For these priority projects the federal gov­ernment and the Free State of Saxony provided financing totalling ca. 4.8 million euros. In September 2003, the federal government and the Free State of Saxony, without prejudice to their respective legal

positions, signed an administrative agreement re ­garding remediation of formerly abandoned Wismut sites in Saxony. The aim is similar to the Wismut Proj­ect: mitigation of environmental damage in order to restore a wholesome and unimpaired environment for the benefit of the public in the affected former mining regions and provide impetus to positive re ­gional development and economic revival. Financing

is provided equally by the Federal Government and the Free State of Saxony to the tune of 78 million euros to terminate the effort by 2012. An advisory council on remediation was established to steer and control the rehabilitation of formerly abandoned

Stewardship site Annaberg­Buchholz, Drei Könige waste rock pile at beginning of clean­up operation (2007)

5Stewardship sites

Stewardship site Annaberg­Buchholz, Drei Könige waste rock pile, protective wall around remaining conical piles after com­pletion of remediation (2008)

54 5 Stewardship sites

Wismut sites. Wismut GmbH is mandated with the implementation of the remedial projects. By the end of 2010, 58 million euros were spent for the remedia­tion of more than 150 objects located at a large num­ber of sites in Saxony. A considerable number of reclaimed areas have been restored to local commu­nities for sustainable reuse. Talks are expected to begin in 2011 on a follow­up to the administrative agreement between the Federal Government and the Free State of Saxony for the period starting in 2013.

Stewardship site Schneckenstein, waste rock pile #241 after remediation (2010)

Stewardship site Schneckenstein, pit shaft 241, central shaft and waste rock piles in the background (ca. 1948)

55

Due to decades of a policy of secrecy followed by Wismut, in 1990/91 the newly established Wismut GmbH and their activities were confronted with strong mistrust and reservations on behalf of not only the public and the media but also the nascent regula­tory authorities. At that time, Wismut was almost daily in the news, mostly providing unfavourable headlines.

Purposeful and transparent information policy

and meaningful outreach work were therefore high on the agenda for the Wismut GmbH. The change of image came as a result of numerous confidence­building measures, but first and foremost of success­ful remediation that was visible from the outside, conducted by the federally­owned Wismut GmbH.

Nowadays Wismut GmbH presents itself by numerous public outreach activities as an efficient remedial company. Local communities, districts, public authorities, technical experts and environmental groups were involved in the development of remedial concepts, the identification of remediation goals and proposals for the reuse of reclaimed properties. Information centres were established at remediation sites in Saxony and Thuringia. Wismut GmbH keeps the public informed about remedia­tion progress by the press, online, “Open Days” at the sites and presents itself at national and international symposia. A number of Wismut’s outstanding remedi­

al projects were presented on the occasion of the 2000 World Exposition EXPO 2000 and the National Horticultural Exhibition held in 2007 in Ronneburg.

Since 1991, more than 1.5 million visitors from Germany and abroad were welcomed to remedial sites in Saxony and Thuringia.

A particular form of paying tribute to remedia­tion achievements and regional development was the Saxon State Award for Building Culture 2008 award­ed jointly to Wismut GmbH and the spa town of Bad Schlema for their joint submission „From Death Valley to Spa Town“.

Visitors at Open Day, Ronneburg site

Environmental reports of Wismut GmbH

6Public relations

56

Evidence of the vast artistic and cultural activities of SDAG, some 4,100 works of art (paintings, drawings, graphic art among others) dedicated by 450 artists are owned by Wismut GmbH.

Artists working for SDAG Wismut came notably from the Academy of Visual Arts Leipzig, which estab­lished its reputation as the “Leipziger Schule”, and the Dresden University of Art. In addition, the collection comprises works by artists from art colleges in Halle, Berlin, and Weimar. It also includes many works by amateur artists working in visual art clubs at Wismut. Other contributions were provided by artists from Armenia, Hungary, Bulgaria, Poland, and Russia.

About half of the works, which were for the most part commissioned, are thematically related to min­ing. Their focus is on underground scenery, mine landscapes, pit shafts and mine buildings. There are also a great number of miner portraits and group pic­tures representing four decades of uranium ore min­ing. Others works include still lives, landscapes, nude studies, everyday scenes, animal representations, or literarily inspired paintings.

Ranking as the largest and most important of GDR corporate collections, the Wismut GmbH arts collection will continue to be presented to the public.

7Arts collection

Nikola Kiriliev: Blackbirds over mine dumps, 1989

57

In 2008, a project was launched to comprehensively document and depict more than 40 years of uranium ore mining by Wismut in Saxony and Thuringia as well as rehabilitation results achieved after 1990 by Wismut GmbH. Scientific studies and documentation will also include the subject areas of politics, econom­ics, environment, and social affairs. International comparative studies have been proposed, with the aim of providing benchmarks for the classification and evaluation of Wismut corporate history, particu­larly with regard to business regime, levels of sophis­tication of mining engineering, environmental con­cerns and radiological protection, safety standards, economic viability, and employee social benefits.

To this end, a project team has been formed under the overall responsibility of the Chemnitz University of Technology. Financing is ensured by contributions from the Ministry of Economics and Technology, the Chemnitz University of Technology, the Gerda Henkel Foundation, the Friedrich Ebert Foundation, the Munich­based Institute of Contem porary History, and Wismut GmbH. Study volumes documenting Wismut corporate history will be published in summer 2011. This publication will constitute a major work of refer­ence regarding Wismut corporate history.

8Documentation on Wismut corporate history

May day rally in the 1960s

Order no. 155, Soviet Military Administration, 1945

58

Since uranium ore mining was terminated and reme­dial operations started 20 years ago, remedial results achieved by Wismut GmbH in rehabilitating the lega­cies of former uranium ore mining operations are clearly visible at all sites in Saxony and Thuringia. More than 80 per cent of the physical work had been finalised by 2010. Environmental impacts in the affected areas have been significantly reduced by the remedial efforts.

Today, the rehabilitated areas once again have become home to a multitude of animals and plants. A bio­monitoring programme is helping Wismut to keep track of the return of the indigenous fauna and flora.

The work completed so far has provided a sound basis for the accomplishment of future tasks. The fed­eral government will continue to fund the effort. According to current levels of knowledge in 2011, sub­stantial remediation work will be completed after

2020. Thereafter, some objects will require post­reme­dial care, and long­term tasks will have to be per­formed at nearly all reclaimed sites. This includes in particular the interception and treatment of flood water and seepage, maintenance of covered areas of waste rock piles and tailings management areas, the operation of a vast environmental monitoring system as well as mine inspection tasks. The time frame required for these efforts cannot be specified at the present time.

This brochure provides a general overview of the remediation work performed by Wismut GmbH, including its mission, goals, and achievements. In the annexed flyer, tables and graphs provide figures on key processes and developments of Wismut GmbH. For more complete information concerning the Wismut Project, please log onto the Wismut GmbH website at (www.wismut.de) or consult the extensive literature available on this subject.

9Summary and outlook

Rose chafer (Cetonia aurata) on large pink (Dianthus superbus)

59

The rehabilitation and reuse of former mining areas establish key preconditions for economic devel­opment and job creation. Continued remediation at formerly abandoned Wismut sites will provide local communities with new possibilities for the sustaina­ble use of reclaimed mine land.

Reclaimed waste rock pile landscape Schlema site (2010)

60

This brochure is published free of charge as part of the public relations work of the Federal Ministry of Economics and Technology. It is distributed free of charge and is not intended for sale. It may not be used by political parties, candidates or electoral assistants for purposes of election campaigning. In particular, the distribution of this publi­cation at campaign events or at information stands run by political parties is prohibited, and political party­related information or advertising shall not be inserted in, printed on, or affixed to this publication. The distribution of this publication to third parties for purposes of election campaigning is likewise prohibited. Irrespective of when, how and in what quantity this publication reaches the recipient, it shall not be distributed or used – even outside the context of election campaigns – in any manner that suggests bias on the part of the Federal Government in favour of specific political groupings.